you have a good design. heat is always a problem, but with a good exhaust fan and the ac in the window you should be fine. just watch with leaving openings at the top of the tarps. you don't want light from your MH bulb disturbing your flowering. but its a good setup it should work.
first time grower here. just want to say love this site. lots of info,have learned a lot. already started a grow journal. check it out. now if you don't mind my bong is calling my name. peace bongsmilie
https://www.rollitup.org/grow-journals/164177-narpal-first-ever-grow.html
This is my first attempt to grow. I will be getting clones from a friend. Anyone who has had the opportunity to smoke narpal knows of it "pain killing" narcotic affect. It is a very powerful strain. To much of this shit and you will be out for the count.
I have had some help from a friend...