Yeah the ideal temp to have in your tank is from 32-28 (depends where your thermostat is), as long as you have an area of the tank ~28 degrees you should be fine, (that's for carpet pythons anyway). If they have warm areas of the tank and cool areas it gives them a gradient across the tank to move from warm to cool or whatever they feel like.
i normally just turn my lights off over the night (Dad never installed a timer switch when he built the tank for me :cry: ). But i live in Ballarat now and the nights are getting DAMN cold, so i just use the 60W blue globe overnight (I use a 100W clear one during the day), so she doesn't get too cold... the blue one is fairly dull but puts out some heat (and cos it was a reptile light i think it puts out a little UV too)., but it would at least be less harsh on their eyes. Think about it... if you couldn't close your eyes to sleep, wouldn't a 24hr light get a little annoying?
With my setup i have a 2ft flourescent reptile light for UV (it puts out UVA + UVB) to replace the natural sunlight, and i have a 100W lightglobe (regular everyday globe) for heat. at night i usually turn it off for her, but through the winter i'm replacing the daily globe with a 60W black light for a little extra warmth and because it is less harsh on your eyes than the regular light globe.