I don't know if this was mentioned in one of your other posts yet, but make sure the girls are not too young/small to breed right off the bat. People wait for the females to get to different weights, much like the debate about breeding small female bp's. I won't breed a female under 250 grams, and so far we have been waiting until they right around 300.

Good luck with your colony, and I agree that line-breeding is not that big of a deal, so long as you freshen up the colony on occasion.