He prefers auto regulation, then the volume should take care of itself. For example, if you have just worked chest/back the smaller muscles will be slightly fatigued and you will most likely get less volume. If you work arms on a separate day you will get more volume.
If your not comfortable using auto regulation then
My general guidelines are:
15-30 when you have only one exercise for a muscle group, for priority muscle groups, when training with lighter weights, or just have a higher volume tolerance
10-20 when you have two exercises for a muscle group, or have a moderate volume tolerance
5-15 of isolation exercises or smaller muscle groups when you already have trained 1-2 base lift or overlapping exercises, when lifting very heavy weights, or if for different reasons, have lower exercise tolerance.
These are a few years old and he may have changed his ideas though. http://translate.googleusercontent.c...8Qz5GVL0z1lY6Q