They'll poop and pee when they wish. Typically, they pee more than they poop, but it can be true that neither is all that frequent. Sometimes they can go weeks and weeks without a poo, even if they are eating well. (Consider...you don't go "poo" after each time you eat. ) Anyhow, their metabolism and digestive systems are not really comparable to ours.

As for feeding...they really don't need tons of food to eat. Many ball pythons in captivity are way overfed compared to what they would normally catch and eat in the wild. This isn't to say we should try and mimic wild conditions with long forced fasts and sketchy meals....just to point out that if he's getting 50g of mice a week, every week, all year long...that adds up to way more than a similar sized snake would end up eating in the wild in the same year.

You can try moving up to a single rat if you want. The snake may or may not take to it easily. Only way to know is to try. BUT...if you do...and if you feed live...then be prepared to deal with an uneaten live rat. Have a plan for what you are going to do with it. (Keep it...kill it....or can you take it back to the pet store?)

When feeding two live rodents....you DON'T put them both in there at the same time. Put one in and let the snake kill and eat it. Once the mouse has moved down into the belly and the snake has realigned its jaw, it will usually start sniffing around for more and return to the "hunt mode"....when it does, you introduce the second rodent.

If you're feeding f/t or pre-killed, then you can offer both at once if your snake doesn't need the zombie-mouse-dance to entice it to eat them.