10, that's what these guys use too....
http://www.progressiveautomotive.com/Boxing.htm

My father in law works in a metal fab shop, so i was going to try talk him into cuting them out on his table. Just need to figure out how/what measurements he needs to set it up.

As for the front end, i'm not sure. I'd really like to put a MII in it but, i have a 6 month old and another on the way. So i'll have to see where my play funds are when i get to that point, But in all honesty, i'll most likely end up running the stock front end for a couple years(if i can get the motor in there with the steering gear there). What did you use for the rear end, Spring wise? Did you get a kit or fab up brackets and find springs? Im thinking of doing a TCI kit and my 10 bolt