300 grams is still small enough that he won't be pooping that often. I've noticed an increase in size and rate of pooping at about 600 grams, so long as the snake keeps eating.

Ball pythons don't necessarily "musk" though females do have scent glands used mostly, I believe, in courting a mate. Urates smelling a lot is strange, do they seem out of the ordinary as far as consistency goes? Just in comparison to your other snakes.