I switchedd to GT Entrada to get a lower GPI so I could front weight more without getting a log for arrow weight.
I'm doing 90% the same, 2117, but 3" section and use hot melt, then 100 gr. brass insert (lip on insert helps hold the over-foot in place too.
Today at a shoot, I missed the gator from way up on the hill and hit the rock dead solid! Sparks flew like crazy. I thought...dead shaft!
Went down and the point was all scourged up, but the shaft was perfect...tapped it, bent it, wrapped it on a stick...but it was solid as before the errant shot!
I'd never heard of the tiny collar, but something like the Easton Uni-Bushing set up I guess in terms of protection.
I used Hot melt (brown variety) and been shooting them for a year w/out any issues, but you surely gave me some new ideas!