RHP's are ideal for melamine enclosures. If you do use one then make the enclosure at least 15" high to give yourself plenty of room to work around it for cleaning and securing the power cord. That would also give a bit more room to put a perch under it in case your ball python wants to hang out and bask.
A UTH does work under thick melamine, it just takes longer for the floor to warm up. On the flip side, once it's warm it holds its heat nicely.