Litter Sizes and Sex Ratios

So, I was just wondering if anyone was finding higher/lower litter sizes with different ratios. I'm about to set up my next group of breeders and I was trying to decide if I should try out something different. Right now I have a 1.1 group that usually has 15-18 per litter, and 2 1.3 groups that have between 10 and 12. The 1.3 groups haven't been producing that long so they may pick up in litter size. Anyone seeing any trends?

Depends on the size of your tank / tub.

1.3 is good for cat litter tubs or a 10gal... wouldnt go much higher then that. my litter size have been around 30 per tub..