Rest between sets in GBC?

I thought that in the german body comp workouts you perform 1 upper body exercise and immediately start a lower. A guy I know says rest 30 seconds first. WHat is it?

This has been covered so many times. Do exercise 1, rest for 30-90 secs, do exercise 2, rest 30-90 secs, repeat. Do this for all exercises.

I rest between 15-75 sec between all sets of the GBC program (longer rests for big muscle groups, shorter rests for smaller muscles). Hell, it takes almost that long just to move between equipment and change weights. If you can complete these workouts with shorter rest periods, then I’m impressed.