I might add I'm also debating whether to go "all the way" with 8x10 or not. (I'm also looking at 5x7.)
I can enlarge 4x5 in the darkroom I have access to and it would be "ok" for alt process prints.
The 5x7 would be better for contact prints and I can stick a reducing back on it.
The 8x10 would be better yet for contact prints, I could have a nice scan, or stick a 4x5 reducing back on it.
...granted I don't want to get in over my head.