i think it depends on a lot of factors...how shut down are you...have you been on for years? If so it may not be possible for you to produce natural testosterone anymore...and HCG will do very little for you...might produce some more sperm for you...
I think it would be safer to stay on a low dose (100-150mg/week) of testosterone...I dont have a lot of experience though...there are very good HRT forums though...