Wynn,
PLEEEASE show us some pictures as you go, whatever you've got. I've ALWAYS wanted to do a B-25, but haven't, yet. It is definitely nearing the top of the to-do list though, and I'm doing more homework on it all the time. Mine will most likely be around 56"-60" for two .25's. I would really appreciate seeing and studying yours as you progress.
Thanks!