cracksinthepitch, sounds like ya got it covered, just check the temp at the hotest place in the enclosure that they can get to - on the floor/substrate at the hot end (if ya got a heat mat) or on the highest branch nearest the globe if running heat lights. That should be no hotter than about mid 30's.
All reptiles do absorb heat from above as well, so you may find that the snakes temp is above the substrate temp in your case - using lights. I have measure mine and with an air temp of 25, they will have a surface temp of 28.
I forgot to mention I am using a heat mat, no lights.
I am using an Exo Terra Desert Medium but its wound back to about 1/2 by the thermostat.
My air temp sits at about mid 20's and my two are still eating regular and growing quick - have a hide at each end so thay they can rest in the cool or the heat.
If ya get real obsessive get a non contact thermo and check the python when they are resting, you can take a direct measurement of the animal, or move your thermometer sensor into the hide where they rest.
herpsrule, I'm a long way from an expert yet, but if you have the water at the cool end it can still dry out a bit, the best way is to get some sort of humidity monitor in there.
If they can live under a log in the winter (<10 deg) and cruse around on hot roads & rocks in the summer at night (mid 30's at 9pm) they must be tougher than us.
