All my res's are 90 Gal mixing tubs for concrete or whatever. They are about a foot and a half tall, perfect for sitting under 4X8 tables. I've never had an issue with temps, however my room is air conditioned. Nonetheless, if you have ideal temps in your setup and enough water is touching the surface, then you're golden.
Also, I don't use anything to cover my tank. I had issues in the past with res temps getting high due to the heat the pumps displace. The more the water breathes the cooler it is. Don't worry about mold or whatever, this is as dirty as my tanks get, and that was me missing a couple doses of h202. The h202 is
vital if not using a cover.
I would increase the amount of h202 if this is the method you choose. I use 35% 'technical grade' at 1.7 ml/L. You might want to bump it up to 2 ml/L at the grade ur using or 7.5/Gal. I redose my tanks every 3rd day. At the end of the grow I scrub the shit out of the tanks because what little crap remains will stack up and eventually turn ur roots into mush and make everything smell like egg farts. I was harvesting last week and decided to not bother dosing the tanks while I was cutting. IT only took 5 days and the small pool of water in the slump of my tray had turned the roots and the rockwool green with algae. Trust me the shit is fast, dont miss a dose.
As far as the lineup, use synthetic nutes only as u probably know that h202 will oxidize/break down everything living. My current lineup is H&G Aqua Flakes A&B H202 and cal mag plus. I just replaced Canna Aqua Veg and Flores which was a stellar batch and not bad for the price. Only reason I changed was I wanted to experiment with some bloom boosters and the canna aqua line seems to deny even their own pk booster. I used Hydroplex and had 'okay' Results but still got some burning leaves at the end using only half dose. Since H&G is manufactured by canna, I thought I'd receive the same results and maybe get to try out a good bloom booster without burning anything. You can't beat the price either.
I don't know much about the AN line you're using but im sure none of it's organic and will work fine with h202.