Ok don't think I'm brave enough to go with only 1 support so think ill stick with 2! Right now the support I'm fighting with to get access to my sump is 7" so I think I'll be able to deal with 4" a lot better!
So I did a new drawing (by no means a pro lol!) and I think I calculated this right... 3 doors at 21" each and that's with a 1" overhang on each side. Am I right or missing something? Lol this may change tomorrow!! Lol