Alright guys I dont ask for much help but here goes.  Ive built a few foam cored bows and absolutely love them. The ones I have built have all been one piece bows.  now Im building a 3-piece longbow with foam cores and am kinda on the fence about stack calcs.  In the past I backed off 30% for foam and it got me really close.  Heres where It gets me to thinking its going to be a flop.  Normal stack calc for me on a 50 pounder is .295 with Boo or any wood. when I subtract 30% I get a .206 stack for a 50 pound set of limbs.   Just not sure of this.  

What do y'all think

I've never worked with foam---
and your math is right--as long as you trust your "foam factor" you should be good
  that being said you can always sand a couple LB's off--can't sand them on!
---good luck

Cant see why the 30% wont work all the way around. You know what they say though--you just got to build one to see where you are at.

Thanks I'm just gonna roll with it and see what happens