Hi and welcome to the forum.
I personally feed all my BPs every 7 days. I'm in no hurry to get them to grow faster.
I'd try giving your normal girl a rat pup and see if she takes it. At her weight, I think that would be a good meal.
In regards to your boy, feeding him a couple of mice doesn't sound too bad at all. Like ElliotNess mentioned, obesity isn't going to be a problem with a snake that size.