Congrats on her!
At her size I would be doing small rats every 10 days. I feed my boas smaller meals on a 7, 10, then 14 day schedule (baby, sub-adult, adult) with fine results. You don't need to stuff these guys with food to get them to large sizes healthily: here's my June '10 male who despite not being fed overly frequently and not giving him huge meals went through some nice growth spurts and he's currently on a large (not xlrg, not xxxlrg, not jumbo) rat every 14-17 days:
The tub should last you a while, but note that sometimes when these guys go through a spurt they really spurt! I would look into at least a 4' cage for her, recommending a 6' for female Colombians. I really like Animal Plastics cages.
For feeding in blue: all but one of my boas will eat while in shed so I'd try her if you like.