Hi Steve, welcome to the forum.
In receiving answers to your questions----bare in mind, that you may receive answers that seem contradictory. Lots of us have developed different methods that work best for our particular situations and different experiences.
You can figure roughly 1 lb. of cheese per gallon of milk----this will very some, depending on types of milk and different cheese recipes.
Always go bigger on your vats then you actually need----you need room to stir without slopping all over the place. I originally started with round vats, but mostly use rectangular steam pans now----up to 6 gallons, over that and I am back to my round vats.
I very seldom wax cheese any more-----I prefer vac bagging----but if you insist on waxing-----skip the cold waxing and brushing, and go to hot wax dipping-----I dip at 230 degrees, using a candy thermometer and an old fashioned heavy aluminum pan on a hot plate----this is somewhat more dangerous then a double boiler----with a little caution, all is good. My pan is 10 in. diameter--8 in. deep-----5/16 in. wall----can easily do 8 in. cheese.