Malibuskier,
There’s not going to be a “general” thought here on your original question because there are so few here who get to see anything like an accurate FPct for many HS players, and I’m sure you can understand that. Because of that, its really next to impossible to answer the question.
I can offer you this much, based on our HS team for for the last 7 seasons. http://www.infosports.com/scor...per/images/def2a.pdf
The 1st page of course is a combination of all the players at each position. If you go to the next page you’ll see the breakdown of each position. Its pretty easy to see that of the regulars, anything from .870 to .930 is good enough to keep a spot as the starting SS on a very good big school team in NorCal.
As for your thought about .565 probably indicating the wrong player is there, I’d say in order to really know, a lot more information is needed. The reason is, putting a player into a given fielding position is probably much more likely to depend on his bat and his ability to act as the leader on the field than his glove.
Your question was a very good one, but its too bad there’s such a dearth of fielding stats to answer it well.