Hello Ted, A bit late here but I do have some thoughts on bottom painting. On average I use 5 quarts per coat and almost always will apply 2 coats. I have used many different types of paint over the years but am currently using Pettit Trinadad pro. It is a hard, modified epoxy paint that lends itself to frequent cleanings. Here in the river I do not need its high copper content.
I always apply paint to a smooth surface. I always prefer a thin nap foam roller cover, like used and sold by West Systems. If I can't get these I will use the thinnest nap "candy Stripe" roller covers as they will shed the least amount of fibers when used. I never ever use the longer nap covers. I use only the 7" rollers, The 9" are too long to conform to the surface in many locations. I roll relatively slow. I want a complete and smooth surface covering. After painting is finished, wipe your hand over the surface, You will feel many little "prickly things". This is dust, bug wings,pollen and who knows what else. Overall there will be thousands. I almost always will sand the surface well after painting, 220 grit or finer. As a minimum, wipe the bottom completely with a scotch brite pad. Indeed, I have often sanded longer after painting than before. It's just me. Just remember,, a smooth bottom is faster than the alternative. Good luck. let us know how it all went. Dave