If 80% is fabrication, indeed, 20% may be real.
The reviews came in quick succession, because like most fake reviews on RentMen, they were written at a point in time to fulfill a present purpose. See for example, three reviews (all on on Feb 1!), some by previous reviewers. No narrative, just fabricated for a purpose. His narrative reviews are nearly all written by the same person, with the same errors.
There are numerous accounts on RM, writing very similar narrative and blank reviews for the same itinerant South American escorts, often multiple times for the same provider.
Your criteria for selecting escorts is bizarre - as if they are some kind of product that is pure and gets "used". And taking it at face value, using a review count is an incredibly naive way of measuring how much "contact" they have with the "outside world" (it sounds insane to even entertain something so inane).