basking temp and CHE

Hey guys! Alright, so, I have my 75 gallon tank, and I have a dual dome light fixture. Currently, the weather is changing, and I'm finding that the basking spot isn't hot enough. I had anticipated this for winter (it gets very cold here, and we have the old radiator heating system, so nothing very impressive), and Gabriel has a CHE in addition to a 100W bulb.

My question is, would it be sufficient to just start using the CHE during the day? I assume that since it raises the temp of the tank, the basking spot would start going up as well and it would hit where it needs to be.

My only other solutions are:

-to go up to 150W which I don't like so much because my lights rest on top of my screen and the bulb is big enough that it actually touches the screen
-buy another fixture for my tank so Gabriel can get closer, but I am not looking to spend tons of money (it's not that I'm not willing to - I just don't make tons and tons of money) and he adores the big rock he has right now.

He is currently basking with his mouth open, so I'm assuming that he's at a good temperature and now he's regulating it. I turned the CHE on and now the temps at his basking spot are from 105-108 (he's about 9 months, or so I was told. I'm not convinced.).

So! Yes, I just wanted to know if this is a good solution, since winter will be here soon. Also, I don't keep any heating on at night, but my house does become fairly cold in the winter and Gabriel's tank is glass. Is there a particular temperature where it would be too low for him and I should use the CHE? I know they're accustomed to cooler night temperatures, but I wasn't sure if there's a low that's too low.

If the 100w is putting out a nice bright white light, then you can supplement the heat with a CHE. It sounds like having the CHE on is getting the basking spot to the correct temperature. How is the cool side? If it's possible, you may want to hook a thermostat up to the CHE so that it kicks in at a certain temperature range. I'm not sure if you can isolate it from the basking light in a dual fixture though. Keep a close eye on the temps but it sounds good for now. Overnight, the temps in the enclosure should stay above 65 or so. If they drop below that, the CHE can kick in just enough to bump the temps into the high 60s or low 70s overnight. During the winter I used my CHE on a timer overnight and it sat pretty high up (25'' above the floor of the tank) and that was plenty.