you don't have to heat itin hot vinegar, that bath called a pickle is used to clean the junk that coats the surface when you anneal and work with it. Until you work with it, you don't really understand how dirt and encrusted with gunk it can get.
BTW there are different grades of brass. Some are quite a bit stronger than others. I'll look up my old supplier. The stuff in hobby shops is the softer version because it is easier to use by the general public.
This company sells small sheets of brass. The ones i use to work with are 4' x 6' I doubt you will need that much. Otto Frei, is located near me, and the people very friendly. They might even carry 14 guage if you ask them.