Well aside from smoking Bud this happens to be my area of expertise, as I am a Master Electrican. You do not need a sub put in if you are going to upgrade to a 200A service. It will just cost you money that you dont need to spend. What you do want is (2) dedictated 20A ckts and (2) dedicated 30A ckt installed (possibly (1) 50A ckt if your using a stand alone heating or cooling system). Those four should give you enough power. Run your lights off the 30A ckts and everything else on the 20A ckts. Alternate the lights between the 2 ckts aswell as the smaller things for the 20A ckts. This will help distribute the load evenly, thust causing less breaker tripps. Make sure when he wires the room that he alternates ckts along the wall and in the ceiling. Once again distributing load properly makes hugh difference. That is all you should need. Whatever cover story you give is on you, but speaking as Electrican the gym idea does sound around the lines of what a gym would draw, power wise. Good Luck and Happy Smoking.
