You can just adjust your "bulking" diet according to how much fat you feel you are putting on. If you have genetics like me, and can lose fat quicker than you gain it, then it should work.

A lot of cardio will help also.

My best advice if you are on juice is: Just gain as much weight as possible and cut down later. You will like the results if you work hard enough at it. Chicks dig a gut now adays.