Is this acceptable??

To have the temps on the cool side higher than normal as they shift? Right now, I don't have a stat on the cool side UTH of her tub and it's being controlled by a rheostat on a timer. During the day, those temps are fine and in just the right range. But at night, the UTH has to come into play.
The timer is set to come on for 15 minutes every hour(since that's the minimum it can be on for) and that has the temps fluctuating anywhere between 79 and 86...sometimes as high as 88. There's nothing else I can do about this at the moment, since I'm waiting on a new stat, but I was hoping that too high was a lot better than too low.

Should be fine... Just like in the wilderness, Temps fluxuate. As long as it isn't a dramatic change or a constant change, it should be fine.

I'd say a little too high is better then too low. But it's still not good!
Nothing more then 95F and nothing less then 79-80F

But I won't lie to ya, my cool side is 75-80, so look who is talking. and this is probably why my snake won't eat! I'm assuming! and my hot side is like 92-95. Which is ok! I think 95 is too hot myself but I hear it's OK. So it's probably OK!

GL!

I think 95 is too high personally. I stick to about 90-91 to be honest, with my smaller bp's that i have in the 15 qt tubs i have them at a hotspot of between 89-90. I used to have my temps high up like that but after a while of doing it like that, i think my snakes like it a little cooler.

Oh, the warm side is perfect sitting at between 90-91 at night and 92-93 during the day since it's on a t-stat. In fact, that's where she is right now. I think she got tired of the constant shifts on the cool side. My concern is that the cool side temps are always shifting through the night. But, that new stat should be here next Tuesday, thanks to Josh, so we only have to put up with this till then.

Another question, mostly to the experienced long time keepers: Do you think that constant shifting is going to hurt her in any way? As I said, the warm side is constant so she at least has that.

Nope.

She will self regulate, so she will do what she thinks is best.

As long as it isn't harmful temperatures, you will be fine for the interim.