I would suggest setting up the tub UTH, substrate, hides, thermometers, water bowl with water and T-stat before you get the snake. Well before, I have personally never had a tub hold more than a 2-3 degrees over the ambient air temp, this is with your low end still very cold and it may take more figuring to keep the correct cool end temps. This is ALWAYS best done with out the snake in there. Patience Royal Pythons are a long lived animal there is no point to rushing in and having the animal suffer. Take your time and get it right before the snake is added into the mix.