CPES, How much do you need?

I've been reading alot of build journals and sticky's on CPES but nonody mentions how much to get for their tears. I'm building a 5' x 8' benroy and can't decide how much to get to cover it.
Cliff
Cliff
or t n ttt for short (tnttt.com)
https://www.tnttt.com/
doug hodder wrote:Cliff....if you want to build up the sides for a smooth finish prior to painting, and lay glass tape/cloth...I'd recommend just an epoxy. The CPES will penetrate...but after the first coat....that's it! It won't penetrate any more and doesn't build like an epoxy would (quickly) for a smooth finish. It also won't wet out cloth or tape like an epoxy would. Just my opinion however, others will probably vary. Doug