Hey brother. Idk where the Q is but very nice.
Idk what tent you are using but I have a tent more or around the same size. I even have my 70x70x160 inside my 150x150 for my flowering photos.
RH will be a nightmare. The best way to combat this is to set up your intake as an exhaust 500m3 should be enough. I have 2 280m3 going and I get a perfect Negative pressure seal with a open vent at the bottom left hand corner and exhausts are set up on the right hand side helps draw in o2 therefore bringing in new co2, and I've a 180 fan to cool my canopy and help with air flow through plants it'll also help cool your light.
Good luck bro..