Calculating the C-34 total wetted surface is not trivial! I did this about 10 years ago using the Newton-Raphson method, and determined that the total wetted hull surface area was approximately 230 sq. ft. (+/- about 2 sq. ft.) Both sides of the keel add another 36 sq. ft., and both sides of the rudder yet another roughly 14 sq. ft. for a grand total of very nearly 280 sq. ft.
"In principle" a gallon of bottom paint should cover about 400 sq. ft. However, some paint inevitably adheres to the inside of the can, some stays adhered to brushes and rollers, and unless replenished some of the volatile components evaporate while one is painting. Thus, actual bottom paint coverage is probably somewhere between 330 and 350 sq. ft. per gallon.
In painting Pleiades bottom myself for the past ten years I find that if I add about 10% thinner, I can cover everything with one coat, and still just barely have just enough to apply a second coat to the rudder, and from the waterline down about one foot, which is the area that tends to accumulate the most slime during the season. I typically swim / scrub just below the waterline about 10 times during the sailing season. Using Interlux ACT ablative bottom paint I have found from experience sailing in NE waters it can "just barely" withstand that much scrubbing before I start to see a bit of the signal coat (e.g. blue just visible through green)showing through.
I hope this was helpful.
Dr. Paul F. Jacobs
Pleiades, TR-FK
1990 C-34 MK1.5
Wickford, RI
