SCUBA here. Go to a reputable dive shop and try several on. There is no other way. They have to fit your face and create an air/water tight seal. Everyone's face is different. A smooth shave is necessary if you want a really good seal. The people at the shop will show you how to test if it fits. You'll spend about $100+ for a good mask and cheap snorkel.
Completely agree,
Mask you have to try on, so either order several online or go to a shop and try them.
Fins won't make a big difference for leisurely dives. Most snorkels come with a good purge valve now, vs the old J tubes
I'd rather have a good fitting mask and ok snorkel/fins than the other way around, otherwise you will be fidgeting with leaking/pressure points, etc
