Ok a couple of things. Your ball python doesn't want a basking spot. They don't want to come out and bask. Think about it like this. If I come out into the sun I get eaten by a bird of prey. Your snake will do best with two identical tight fitting hides with one opening each. You should then try to provide appropriate warm and cool temps under those hides with an ambient temp above 75 at the bear minimum.

Now your first question was "How long does it take to digest?" The answer is a lot longer if your temps are too low, which they appear to be. You should invest in a UTH and a thermostat. BP's will digest their meals in the burrows of the animals they eat or other appropriate burrows. Its for this reason that they get their heat from the ground they are sitting on, not the sun. Your BP, never ever wants to come out and sit under a hot lamp. It will only do so if its that or death.