I'm thinking that I would use the following equipment, all of which I have already:
aquaclear 50 filter
Ocotpus BH-100F skimmer
18", 36watt T5HO
possibly a koralia 1 if I need it
currently, the only fish I still have in the 40g is a falco hawk. I'm probably going to try keeping him in the 10g, and will see if it feels too small. he'd be the only fish, and if he turns out to be too much for the tank to handle I can always rehome him.
does this sound like it would work? I'd be doing weekly small water changes of a few gallons, and I'd probably get an ATO to deal with evap.