I am reading this with great interest because I also do the same type of routine. I do four sets instead of six but it is the same concept. Is it better to fatigue the muscle than to do the same weight? I used to do step increases and still kind of do it sometimes.

Also, if you're doing at least two day gaps between muscle groups (ie upper body/cardio/lower body/cardio then back to upper) is that sufficient? Or by rest does it mean no weight training? Lower body rest is the worst because everything requires lower body!

Great thread though and I am sure many people appreciate the information here.