In my opinion, the PPC programs have a problem: most people who are in them are, in turn, in most of the programs that can be promoted in them.
Of course, every day there are new members and is always possible to find someone who isn't yet in SFI and be tempted to discover what is it (in fact, that's how I ended here xD), but as I see there isn't a special trick to get it beyond the three P's: