So My plan is to use form-a-drain for my footer. The outside wall will drain into a sump well and be pumped out. The interior wall will have it’s own sump pump/well. So for the basement slab I want to put 3-4″ of stone then 3″ of foam insulation and make that flush with the top of the footer. then pour my 4″ basement slab. My only concern is I will be covering up 3″ of the top portion of the 6″ form-a-drain. Since I’m not connecting the inside and outside form-a-drain together my thought is I will be fine. The issue is the form-a-drain has a separate top and bottom cavity that I didn’t realize was completely separate….I assumed it had holes in it. So I could drill some half inch holes through the bottom of it every 3′ or so to connect them. This would allow the whole thing to fill up if it was absolutely down pouring outside. Thoughts on this? I could put the foam on top of footer but that would cost me 3 more inches of stone and labor to spread it and I would lose 3″ of headroom in my basement. If this is the consensus then I will complain and not want to do it, but in the end do it if it keeps my basement dry. Thanks 
(similar to the picture)