I just use a shielded FL for day time and a blue 'tube' led for night.

FL fixture... http://www.rona.ca/en/18-in-fluorescent-fixture

Something like this for led.

http://www.ebay.ca/itm/18-30-42-57-6...item2ecf0d7e53

I just use screws to mount it just like any other application.

Yes they do change the Relative Humidity. (relative to temperature if the air temps change it MUST change) They increase the air temp and because of that they change the saturation point (increasing it) and that means you need less RH% to get a good shed. Any heat source that heats air will change the RH.

No you cannot regulate it with a proportional stat it flickers and goes foolish. The range of ambient air temp is dramatic (74ºF-86ºF easily some say wider that this) you don't really need a stat to hit inside a 10ºF spread. I just use a timer, I change it 3 or 4 times a year as the room temps changes with seasonal shifts.