Given that you are still in the 'make up for lost time/fattening up' stage, you would probably do well sticking with what you know they will eat. If you try a switch now they could go back to stubborn 'make the snake momma wanna drink' mode.

Don't ppl typically go to rats to be able to offer larger prey at one time instead of multiple mice? and perhaps slightly more nutritious? If that is the case, your wallet would need to decide as multiple mice probably cost more than one fat juicy <albiet frozen> rat.