By not gaining much weight do you mean its unacceptable? If not how much weight are you willing to gain... if you could throw out a sport and maybe position that might help.
If its a sport with clear weight classes, Im thinking sports such as boxing, wrestling, etc. Id stick to Var if you can afford it.
If you are able to gain some weight and simply want to minimize weight gain due to loss of endurance, etc. Id say you were safe to run a low dose of test as a base and then throw in a compound such as mast, or winny if its non contact.
HGH would always be an option, but I wouldn't touch the stuff without extensive research and experience in cycling.