Bodybuilders Out There? Advice?

Hey I am not new to lifting but am new to prepping for a competition. I want to do a Natural show in the fall and am currently in a bulking cycle. I am wondering if I should start taking a Creatine or a weight gainer to supplement. I burn 3000 cal a day with my job and workout and am eating 4000 a day but unfortunately am eating my wife out of house and home. So I was wondering if a weight gainer with creatine or something would be helpful?

Also, does anyone know what supplements are legal for natural shows? I was looking at testosterone boosters, but am not sure. I am worried there are ingredients in there that are not listed since supplements are not regulated like food.

Any additional advice would be great! Thanks in advance