If water spills on it and it is on full blast, I think it could possibly crack the glass if the water is cold enough. I haven't really heard of this happening though. I like to keep my water bowls on the heat a little bit to help produce some humidity. This also heats up the water so if it spills, it shouldn't crack the glass.

I don't think the size is too bad as long as you have an area that cooler so the snake can thermoregulate.

Get that thermostat ASAP! It is the most important part of a setup. It is too bad the UTH instructions don't tell you that you need one!

Cool side sounds fine as long as you get a surface hot spot of 90º

Also remember that your thermometers have a big impact on what temp you think it is. If you are using Digital thermometers with a probe then you are good to go. If they are analog thermometers, you will probably want to exchange them. Make sure the thermometers are where the snake spends its time, on the bottom of the enclosure. I see so many people come in with those stick on gauges at the top of the tank, what good are they al the way up there? lol

Kudos to you for getting things set up before you get the snake!