I'm planting Kiowa this year, so I can't tell you anything from experience. I too have heard varying sunlight hour requirements for blackberries, but I would have to conclude that the more sunlight the better, if you can manage it. If not, I would suggest keeping them far enough apart not to crowd each other. Like 4' apart.
Kiowa is not the most upright of the upright varieties and you can count on them flopping on the ground for the first few years. After that, topping the canes will be required as you have described. Since you are planting along a fence, you might be able to afford a single support to each cane as necessary.
Nothing I've read tells me that you need to worry about trimming the laterals. I would only do so to prevent congestion between plants. Or unless they droop down and touch the ground.

My erect blackberries are planted against a brick wall and they are arching out about 8 feet. They don't really make bushy growth as they do long elegant arches like willow trees. 4ft. high by 8 foot wide.

But I decided not to trellis it because it is erect. The canes are mobile enough that if you wanted to pull them back and tie the full grown arches to the back of the wall at any time during the growing season it would be easy.

However, yours having thorns, do not put it near your veggie garden, you cannot control it enough to get into such a small space.
Your second option sounds fine.

Gardenspots:

If you want painless care, please do not plant any thorny blackberry variety. Find another blackberry variety that is thornless. Thornless blackberries are every bit as good as the thorny varieties.

Blackberries are not permanent "bushes" at all, but biennials that require removal of the spent, fruited canes every year. New canes also grow up every season, and not necessarily in exactly the same spot as the old ones, although blackberries do not spread as aggressively as raspberries.

Not only are thorny varieties more uncomfortable to pick and prune, they are a royal pain when the time comes to remove the spent canes completely, which happens every year. Blackberry thorns will actually penetrate a cowhide glove in good condition, to say nothing of what they will do to you when you are not wearing gloves.

I grew three varieties of thorny blackberries for many years before finally tiring of shedding all that blood, and planted Doyle and Triple Crown. These are long-caned trailing varieties that require support, but there are several erect-caned varieties you can plant that should require little to no support. Find one of them and don't plant anything thorny. You will be glad you did.

Don Yellman, Great Falls, VA

Hi Gardenspots-
I saw this post yesterday, and was going to reply to you today, but I see that the wise Don Yellman has saved me the trouble. You really want to reconsider your thorny choice. Thornless varieties are just as good, if not better than the alternative. It really seems like a no-brainer to me. Under almost no circumstances would I plant a thorny blackberry when there are there are great thornless varieties like Triple Crown, Doyle, Chester, etc. (Now, if you were talking loganberries or Tayberries, or some other hybrid like that, then, yes, you may have to settle for thorns)... But, in your case... If I already had thorny blackberries ordered, I would change the order, or simply order new ones.

I grow my thornless blackberries about 8 feet high on a sturdy trellis which you can see at the link below. I'm making a 24' trellis this year for another 6 plants. Good luck! -Glenn

Good luck,
-Glenn

Here is a link that might be useful: Blackberry trellis

Thanks for all of your input on this. I have been away from the computer for the last few days so I didn't get a chance to get back to this.

I am going to try planting it near the house and be ready to trellis it if need be. I can always move it I guess if it doesn't get enough light. I only have one plant and it should have some room to expand there, provided it gets enough light.

I did want a thornless variety, but in doing all of my research and talking to the folks at the various nurseries in town (not the big box/chain stores, the real landscaping types) I determined that Kiowa is the best variety for this area. I know the thorns will be a pain in the neck, but this is apparently the best variey by far for this area and weather conditions.

The nurseries have just gotten the new plants in and the one I went to to purchase my plant had approximately 60 available plants and probably 40 of them were Kiowa and the other 20 were other varieties...two different thornless and another 2 thorny varieties among those 20 plants. So, the Kiowa is overwhelmingly the choice for this area as far as what gets sold and does well so I decided to fight the thorns. I was also told during the researching phase that thorny varieties will produce up to 30% more berries than the thornless varieties and since I only have one plant that seemed like another good reason to go with it. Of course, I don't have the faintest idea, I am just going by what the professionals tell me. It still remains to be seen if I can keep it alive and get it producing. It's beginning to leaf out in our spring-like weather. It's supposed to be 80 degrees today.

I had 1500 Kiowa at one time. You enjoy that plant and size fruit and thorns are not that bad if don't fall into plant they only stick in you when come out bush. When plant plant drive up 2 to 3 T-post around plant tie hay string to one post walk around bush and pull sting or cord tight and tie post kiowa will be so heavy with fruit it need surport if wind get over 25 mph a thumder storm with wind blow any blackberry plant over wind shear at 40 to 60 mph if never had anything blow off porch you be ok lol. There production and there production on blackberry plants 3 Kiowa plant give more than 3 family needs other plants take 15 for 3 family. Kiowa large fruit and large plant so give all room can at planting am going to give you pruning instruction for Kiowa in Texas it differ from what read on net or from deap freeze parts usa plant at least 6 foot from anything main cane prune to 60 to 75 inches tall laterals are limbs cut to 30 inches each that make plant total of 60 inches across if laterals grow off these limbs are laterals cut to 18 inch lenth the more 18 inch laterals your plant has more fruit you have if fruit at that bud you have 5 blackberries if grows to lateral you have 20 berries from that bud position. About trilis if use half of first year it be just right rest plants life. What braking buds is call handle so willbe removed later in 09 may june what comes from crown is growth that save for fruit in 2010.

I planted Kiowa last year here in East TX. Even though they seem to produce a lot better than my thornless variety, I HATE doing any work around them. The torns are huge and they cover every inch of the canes.

Nick:

If you want high production, and are able to put up a trellis, Doyle is the trailing thornless that fills the bill. Should grow fine in East TX and Central TX as well.

Doyle is an excellent berry (I also grow Triple Crown) that will outproduce anything I have ever seen. Of course, I have not seen it all. A couple of years after I first planted Doyle I made ten gallons of wine from 4 plants, and there were still a lot of berries left over. I used pure juice for the wine, no water at all, and 5 lbs. sugar in each 5-gallon carboy. Champagne yeast. It was very good if I do say so, and I am no winemaking expert. Took some out to my relatives in California and they were amazed.

No more thorny blackberries for me. I just hate the thorns. Couldn't even get my spouse to pick them, but she seem to enjoy picking the thornless.

Don Yellman, Great Falls, VA