RE: Tank for Ys63
10oz to 14oz is typical of the fuel tank sizes used with the 63 engines. I would say if you are flying and Astro Hog you should get about 8-10mins at normally lower throttle settings of 1/2 power or so on average.
I have a model with a 63 in it and an 11oz tank. It gets me right at about 10min flying time.
Troy Newman
Team YS