I will add this, even on a big field that is clear, that STILL does not mean someone (that stopped thinking) can't land in a bad spot and run into parked aircraft.
I know, I saw the aftermath at our field (no injuries to people, broken glider, broken towplane).

Max number of gliders has a lot to do with field size & approaches. Huge field with 360* of flat approaches should be able to handle more gliders that a small narrow field with trees on multiple sides.

I have never been to Nephi, so I can't comment on the site.