I second what JAD said. I stay away from the bats that are lighter than -10. So, I would guess a 29,19. I buy the old yellow or blue catalysts, for about $50.00. They are as good as any new bat out there.
One of DD's Easton SRV4B 32/22 weighs 23.7oz., the other 23.8oz. It is a beast of a bat!Be careful when moving up in size and changing brands. I'm finding quite a variance in the listed weight vs. actual weight.
I have a cheap Demarini Tempest 20 oz coming in at 20.04 oz weighed
Demarini Vendetta 18 oz 18.46 oz
Demarini CF5 19 oz 19.5
So I then bought a 30/20 Easton SVR4B which weighed in at ...........22.04 oz!!!
I also have found from posts that Anderson bats run heavy.
My dd is only 8 and playing coach pitch travel ball but is just little bigger than your dd and she is swinging a 28/17 CF5. Weight doesn't slow her down but length does. Her swing is at its best with drop 10 but wasn't a lot out there and dad found a deal. She loves it. Everything she tried that was longer just slowed her swing down, even the lighter ones