I'm just starting to do SF workouts, and I'm moderately fit enough that the lowest few levels are pretty comfortable for me. My plan is to get up through them as quickly as possible until I hit the point where they start kicking my butt (which should be pretty soon, honestly). I don't want to guess and check by trying to do a higher level, failing, and then getting discouraged - I'd rather progress naturally up the ladder, so to speak.
My question: is it okay to do more than 3 of these workouts in a week? Like, next week, could I try and plow through all of L2 on back-to-back days, and if I get under 5' on D3, move straight to L3 on Thursday? I figure it's the fastest way for me to get to the workouts that I really need to be doing... or is it patently stupid for me not to let my body rest between these workouts?