Were you thinking of putting both bushes in the same bed? Blueberry bushes can get pretty big. Pretty much any highbush blueberry are going to want all of a 4'x5' bed. I grow some of mine in raised beds in a fenced garden and some outside the fenced garden just in the ground. You can keep them pruned back to fit your bed, but I wouldn't put more than one in it. That being said, for better crop production, you would want a second variety; a lot of blueberries can self-pollinate, just less effectively.

I started with one blueberry plant, Jersey, that I got on sale from a local nursery at the end of the season. I've gotten berries from it every year, but I definitely started getting more when I planted friends for it in the area. Jersey is in a raised bed that's probably about 4.5' - 5' square, and it would not want to be sharing its space.

The smaller bush behind it on the left is a newly planted Berkley; Jersey was about that size when I got it maybe five years ago - it would have been about 2 then, since it was berrying, which would make it something like seven years old, maybe eight.

(The beds have no bottoms, so the roots go much deeper than the sides of the bed would imply. ... and I need to do some weeding.)

If you really want to try and fit two in the space, I'd recommend looking at half-high varieties, since they'll be smaller bushes and therefore a little less cramped in the small bed.

This is my Northland, purchased berrying about two years ago, so probably around four years old:

Compared to a native variety of the same age:

All pinwheels are identical, so you can use those to compare sizes.

Bloom and fruit timing:

Northland and the native bloomed together; Jersey started blooming a little later, but there was definitely overlap; the native bloomed through out both. Berkley I can't really speak to exactly, since I don't know enough about its conditions before I bought it, but I expect it to bloom within the same range. Northland and Berkley both have ripening berries currently (if I can beat or thwart the birds). Jersey's berries are all still green. The native is there for pollination purposes and to be pretty; I don't even check for its berries, which I doubt I could get without a net or at least a cage on the bush anyways.

Bluegold ... oh, Bluegold. I really liked the descriptions I found for Bluegold, as well. My recommendation would be to make sure that you either buy it from somewhere local or make sure you're getting a relatively large plant. I mail ordered my Bluegold, and I got a fruiting-age plant, but I got a very small fruiting-age plant. This would have been fine, and it settled in nicely, but then it got its main cane chomped by something ... and this poor little plant had this happen to it again shortly after we took off its winter hat (a.k.a. an upside down flowerpot to protecting from critters). We left it where it was, and it has over wintered with a flowerpot and stakes around it. We thought it might just die, since it didn't seem to do much of anything last year, but more recently received a cage for year round protecting, since it finally making its comeback from being munched to the ground repeatedly; its roots are about five; the bush itself ... I would age at infant.

Blueberry Bundtcake has been growing some varieties you might consider but there are many many choices and each has it's own pluses & minuses. I prefer taller varieties because bending to pick is hard on my back. Aside from that you'll want to consider berry size, flavor, picking ease, ripening order, plant vigor, etc, etc. I'll admit that varieties that I like one year I might regret the next year. There are so many things to consider. Sometimes I think it's great that beetles and birds don't hit a variety as bad but then it is usually because that variety just isn't as sweet.