In C/L we rarely need more than a 20C battery. Only problem is that few of the lipo battery manufactures offer 20C anymore. I know that when I ordered 25C batteries from the manufacturer last time I had to accept 30C batteries.
The main thing to remember is that the higher the "C" rating the more expensive the battery will be. There is simply no need to purchase a 65C battery when we only require 20-25C. Why waste the money?