Tub size and multiple rodent feeding

How do you know when your Bp has outgrown its tub? All of my Bps are in 12.5 q tubs (except the mojave in qt) but they are growing super fast. I just weighed my largest and he is over 500g and tomorrow is his feed day. He seems okay with his tub and eats really (REALLY) well. Seems like the one batch of snakes that I got keep nearly every gram of rodent I feed them. I think maybe they were underfed before and catching up. Also, some people feed 2 mice at one feeding to make the ideal meal weight as have I. Anyone feed 2 weanling rats? I was actually really shocked to see this snake weigh so much and the biggest rat I have is around 40 grams.

When my snakes are getting larger than they should be to eat weanling rats and I have leftovers or thawed too many out I will offer a second to a few of my fastest growing animals. Doesn't mean they always want it but they get the option if the timing is right :)