Which series where you're using 10 or 15 and what's you plywood thickness?
I used the 10 series as I felt the deflection rate was more than high enough for my use. It also took up less room and weighs less. However, had I come into a lot of 15 series I'm sure I could have been swayed.
My plywood thickness varies, I used 3/4, 5/8, 1/2, and 1/4 dependent on the strength needed and if I needed a mounting surface. I then did rabbet cuts to lock the wood in place except on the 1/4 because it fit in the slot. It sometimes is interesting to get the panels installed and be able to tighten everything down.
If you don't have it,
MayCAD-64 , is a very helpful tool for laying everything out. And while I started with 80/20, I used a lot of
Tnutz products as well.