In terms of temps, that doesnt sound too bad. You want to be careful though, because if your cold side is 75 during the day, its most likely going to drop a few degrees at night, and I heard anything under 75 is unhealthy for balls.
You should also have two identical hides, one on the cold side and one on the warm side. I have a 20 gal right now, and I have no problem fitting two big hides on either side and a water bowl for her in the middle. Soon to be upgraded tho
Re: Got my temp gun. My cold side is 75, warm side is 91
your hot is fine, and even though 75 isnt all that dangerous, you should try to at least bump it up a few degrees more towards 78-79 would be better, but not something you need to jump on this second
75 is cool for sure what is the AIR temps? they are more concerning than cool surface temps. Raising the cool end temp is not as easy as it sounds, there is no 'this will fix it answer', too many variables.
What type of enclosure do you have?
What is it made of?
How large,how tall?
I am guessing it is an open toped tank? With tanks you have a great advantage in that it is heavy that helps. If this is the case you can insulate the back sides and some of the top (over the warm end) that may help. Raising the room temp is the easiest solution, although not practical for one snake. If you include a fluorescent light inside the enclosure (like hung off the top edge) that will increase the temps with out adding a massive burn issue make sure the snake cannot contact it for long lengths of time and it is fine.
If you are going that far however this might be a viable option. The lower height and close top make it easier to heat add a fluorescent light and usually the cool end temps hold well.