If you plan on getting more snakes in the future, then go with a rack. If you plan on building your own rack using 41 qt tubs then that will be plenty of space for a full grown adult ball python. As far is humidity goes, I understand what your saying about the humidity being to high, i have two RBI 32qt racks and I drilled a good 40 plus holes drilled on each sides of my tubs and the humidity is still in the high 60's - low 70's. People get paranoid that the humidity needs to be this exact amount but the humidity in Africa isn't always that and a little high humidity isn't going to kill your snake. Plus, you'll see as the seasons change, your humidity will change as well so it'll balance out. Mine eat and shed fine and haven't shown any signs of stress or illness and I've had my rack for well over 6 months. As long as their is no condensation and there is plenty of air flow, you'll be good.