Youch!! Butts and Guts is one tough workout. My approach is similar to yours. I stop when I can't go any further and rest (i.e., lie on the floor and gasp!) Then I unpause the dvd and go on.... until the next time I can't go any further, pause dvd, gasp, unpause, repeat as necessary. It takes longer to do the workout this way, but I notice huge improvements each time I do the workout. I did have DOMS after the first time I did B&G, but not too bad since. There's always a little twinge the day after-- from those muscles that don't get used very often, I guess! LOL!
Cheers!
-Karen