Heres my old topic about this, it has a lot of good answers in it!
http://www.ball-pythons.net/forums/s...ad.php?t=71433

Personally I'm going to go with this;
Hatchling-150g : 6quart
150g-500g : 15q
500g-1700g : 32q (males permanently)
1700g+ : 41q

For my cornsnakes, it's completely different.
That's my solid ratio from my old thread that I came up with. :]