Anita, there are two different reasons to prune type IIs as type IIIs. First, all newly planted clematis, regardless of pruning category, should be treated as type IIIs and pruned back at least the first spring after planting. This is to encourage root growth over top growth and to force more basal stems from the crown so that you end up with more vines.

Secondly, after their first flowering, many type IIs can be trimmed back by half or so and they will reward you with more blooms if kept watered and fertilized well. Whether this happens in everyone's zones depends on how long the growing season is their zones. In your zone, I would bet you could get away with it and get more blooms.

Whether type IIs trimmed as type IIIs will bloom at the same time as type IIIs cannot be answered by anyone. You will have to try it in your garden and see. Different clematis will react differently to being cut back and the time it takes them to get back to blooming state. Everyone's gardening conditions, even two people living a few blocks apart, can have microclimates in their garden which can affect bloom times (high on a hill vs. low in a valley, up next to a brick wall that can serve as a heatsink vs. out in the open, in full sun vs. an area where only morning sun is received). All these types of factors and many more will go into determining when any clematis will flower.

I would take the plants out of the pots and look to see how big the root systems are to determine if they are ready to go into the garden. How large the root systems were originally, how well you tend them, and the vigor of the individual plants will affect when they are mature enough to go out. I would bet however that they will be ready by this fall.

Twenty foot wide--hmm how many clematis you could plant there would be about 15 to 20 in my book depending of course the varieties you are talking about. See the post Companion Clematis for Ramona for my philosophy. One thing that I would do however is reconsider planting Nelly Moser and Hagley Hybrid on a west facing fence. Hagley Hybrid is a notorious fader. In my garden, even planting it on the east side of the house, it fades horribly in no time in the sun. I don't have Nellie Moser, but in general the lighter the color of the flower, the more it will bleach out. The darker the color of the flower, the more pigment there is in the flower and the less obvious any color bleaching will be. Living in the PNW, the sun might not be as intense as it is in my garden. Again, you know your zone better than anyone else.

Good luck and don't lock yourself into the type IIs. There are way too many type IIIs out there that will fit your bill than the common Nellie Moser. An added plus, the type III in my garden hold up a lot better to summer sun than the type IIs. Again, living in Seattle, this might not be as much an issue for you as someone living further south.

Hagley Hybrid fades badly here in the Pacific Northwest too. I don't grow Nelly so I don't know. I don't think they would look good next to each other but that is just my opinion.

Type IIs tend to bloom before and after the summer sun here.

What I do to help me figure out what two clems will work with each other is open two windows and load a clematis in each one. Then flip back and forth between the two. **
Personally, I think the two you are thinking of combining might look washed out when planted together. For more contrast, you could try a deeper pink with NM, like Ernest Markham, but there are more. This web site sorts by color
http://www.clematis.com.pl/wms/wmsg.php/321.html&plant_number=279

Photographing the color of clematis seems to be somewhat tricky, but you will get a more accurate color than you would from a plant tag, and some books and catalogs. Of course, the only way to really know if you like how two clematis combine is by growing them side by side.

** If you use Firefox as your browser, you can open windows as tabs. Flipping back and forth between the two windows will be easier than reopening the windows in Internet Explorer.

A little tip for flipping back and forth if your browser is IE: When you have the two pics you want to flip back and forth between, hold down the Alt button and hit tab. That will switch windows. Or, you can resize one window, then drag it over the other picture until the pic in the small window is next to the pic in the large window. I was just doing that at "Clematis on the Web". Have fun..there are so many to choose from!

Here is a link that might be useful: Clematis on the web