I pretty much follow the same feeding schedule Tom posted. I've also been accused of not feeding my snakes enough or 'maintenance feeding' cause they aren't 6' in the first few years. I have some '06s that are going be over 5' this year (some growing about 1/2' faster than the siblings, all on the same schedule). First time breeding will be in 2012, they will be 6yrs old.
I personally will no longer breed any female under 5yrs of age. just my opinion and outlook on it. I'm not saying other people are wrong for doing so. It would be interesting to see how long some of those boas live that are pushed up and bred so quickly...
The feeding schedule seems to work fine for my boas, I've got an '89 common boa that I've had for 14 years, 3 boas that are '98s (albino, het and normal) that I've had for 9 years and all are thriving. They get fed about once a month. If my boas all live over 20 years I feel I've done a good job. (Oh and the '89 was 5.5' when I got her at 9yrs, now estimate her to be about 8', maybe 8.5'.)