Basking temps should be on the opposite end of the cage from where you're adding a UTH (you did say ambient temps). A small UTH shouldn't change them, but if they do you have a few degrees to play with. For more than a few years, all of my basking spots have been set at 94 degrees and my collection is thriving!

In my opinion heating the whole room for one or two snakes is a little extreme, especially if it's a bedroom where you have to sleep.

And if your humidity is too high this time of year (winter==dry), you don't need to add an overhead light (i'm not a big fan of overhead heating). Just stop misting (if that's how you got it that high) or increase your airflow into the cage. Very rare to have humidity too high this time of year without constantly misting the cage, having wet substrate, bad ventilation, etc. Maybe your hygrometer is on the fritz?

-adam