That hide will be fine for hatchlings and young ball pythons, but he may grow out of it quickly. If you are getting an adult it will not fit in that hide.
The humidity should be at 60-70%. Get rid of that heat lamp, it is not needed and will only suck humidity, and they aren't really good for ball pythons in general.
The belly heat from the UTH has to be hooked up to dimmer or it will be too hot. Get a probe thermometer as well to place directly on the UTH (on the glass under the substrate) and make sure it reads about 95F.
What do you plan on using for substrate? Aspen, Cypress, or newspaper are all good choices. Don't use sand, cedar, pine or reptile carpets.