I'd feed in the enclosure. It really is personal preference. IMO, snakes don't get put in a tub to feed in the wild. They're opportunistic eaters, and since they often hide in mammal burrows, they sometimes have food come to them.

They're probly way more comfortable feeding in their home than they are in a tub. Then again, it most likely doesn't matter much to them, unless they go off feed.

I remember seeing something about black lights being dangerous to snakes... I can't remember is someone called BS on it or if it was true. I would unplug it either way, and get a dimmer or thermostat for the UTH (under tank heater).