The pedestals are only a "tap", if you will, off of a 200 amp circuit. This is acceptable because the pedestal itself will never have more than 80 amps on one phase. (One phase of the 2 pole 50, and the 2 pole 30). The guts of the 1st panel in the "loop" does not have the load of the last pedestal traveling through it. If you do this job, from my own experience in one just like it, take precaution to balance the load correctly. Phase 1 in the first box gets the 30 amp breaker, phase 2 in the second box gets the 30 amp breaker, and so on down the line. Your main breaker will thank you for it.
Edit: 1 phase of the 2 pole 50, and the single pole 30.
Edit: 1 phase of the 2 pole 50, and the single pole 30.