Making up a simple rubber band "gun" will improve accuracy of hits to her clit as well as ensuring the guys don't get their fingers!
make her post an add to craigslist and accept everyone to come to the glory hole... the point being she "knows" everyone that's coming, and has to deal with the huge number of people coming before it happens.
How about using the headband set up off a welding or safety shield? You can get cheap ones at the hardware and they adjust nicely. Secured right you could really clamp her head in place.
How painful will the ginger butt plug be in her asshole?
Why not make her ass available to them aswell glory holes have holes on both sides
The men who win the keys will have access to her asshole.