First off, many many thanks to Dr Del for answering questions. RL has me running in circles right now, so I'm not on as often as I'd like to be.
Second, as far as ambient temps go this treatment is meant to stabilize the temps. Although it can help to raise ambient a bit since the heat stays inside the tank instead of dissipating out, it probably won't take it up more than a few degrees from the outside room temp. The best way to give a little boost to ambient temps is with a low watt lamp.
As for larger heat bulbs, I don't recommend them for snakes anyway. The best heat for these guys comes from UTH or RHP. But, if you must use these bulbs, they should always be on a thermostat to make sure they don't get TOO hot. They should also never be closer to the top of the screen than 8 inches.