I think you're on the right path. Make sure you have a thermostat or table top lamp dimmer to control the UTH. If you use the lamp dimmer you'll need an infrared temp gun to make sure your hot spot is at the right temp.

Also, search this forum for he modification to the screen top. Basically, you'll cover the entire screen top with three sheets of aluminum foil (shiny side down), cover that with duct tape, then cut a hole large enough for your lamp. It will help you maintain better ambient air temps and keep your humidity up. I think it's fine to keep using the big water bowl, which will help you with humidity as well. Ball pythons don't typically soak.. often when they do it's a sign of mites.

It's awesome that you're so willng to make changes after keeping them for so long. Welcome to bp.net!