Filling allowance for a Hoga pot still using silicon for foam control

[mendodistilling]

Does anyone use a Hoga pot still to distill beer and other foaming washes which could lead to puking problems. If so, how high can you fill them with silicon antifoam sprayed in there. I'm about to do trials on some beers and have one with a preheater being built and to get the most per day done I'd like to use silicon spray. I talked to Armindo and he suggested for a 380L wash I needed a 500L still, so he is roughly saying 80%.