It worked! Schooling yesterday we stayed (okay, *I* stayed) focused despite fireworks, gunshots, and loud motorcycle surprisingly appearing.
Talented young mare* (not just my ammy-owner opinion) with PSG potential. She's not particularly hot, just Very Expressive about new things.
We are having a little summer vacation that is meant to be about seeing the world -- trail riding (real trails, not tracks around the pastures) and some obstacle training clinics (both of us, together) ... and her trainer recommended "NH" groundwork, for (mostly) my confidence.
The gal we are staying with is a competitive trail rider (the obstacle kind) and enjoys ground work. She has reduced her gelding's startle by "scaring" him until he doesn't jump. She just puts her hands up gives a little jump and says "boo," like you might to a kid, not like you might to the real bogeyman.
I watched her do that to DCM and it was somewhat comical ... very quickly DCM actually stretched her nose at the gal as if "who ARE you?"
I have some reservations because I've seen other horses come out of de-spooking "clinics" fried out of their minds. I know of one lovely dressage Haflinger who was "fun" but a very reliable citizen put with a trainer (?) who flapped tarps over him and made him a jumpy mess. (He was sold to another person and quieted right down. Go figger.)
Experiences, thoughts, opinions? ... all welcome!
*a.k.a. Darling Chestnut Mare