True, there is no way to control ahead of time the number of points per peak in PRM. The place you want to be looking, however, is View > Retention Times > Scheduling. When you have your settings for PRM all set up for scheduled PRM, then this graph will show you the number of concurrent precursors you will get exporting your method. This is covered for SRM in the Targeted Method Refinement tutorial:
It is, however, left to you to know your dwell-time (plus switching time) and to do the mental calculations to figure out your expected points per peak. i.e.
points per peak = peak width time / concurrent precursor count * time per precursor
For example, a 30-second peak width and a 20 ms dwell time for a desired 10 points across a peak will come out to:
30 / 10 = 3 second cycle time / 0.02 seconds dwell time = 150 concurrent precursors
Want 50 ms dwell time?
3 second cycle time / 0.05 second dwell time = 60 concurrent precursors
15 points across the peak just to be sure?
30 / 15 = 2 second cycle time / 0.05 second dwell time = 40 concurrent precursors
This is currently how you would use the tools Skyline provides to answer the question you are posing.
Hope it helps. Thanks for posting to the Skyline support board.