I'd say none, get the hell out of that attic while you still can unless you live in Alaska. I've been there done that... spent the money and just wasn't worth dealing with the temp problems or paying the electric bill for a AC. I did the same thing your doing and insulated the wall, bought a AC and it was still a pain to keep the temp down. Don't do it man, I was told not to when I first started and blew it off. Wish I would have listened...