This has become a huge problem latelyn with my saddle.
I use a wintec 500 AP and a medium wide gullet.
Things I've tried:
-White wintec foam lift pad [extends to back but less lift then the front]
-1/2 and 1 in 'shims' in just the front, they stopped right after the shoulders.
- Medium, narrow, and wide gullet. None seem to want to fit.
Medium wide seems to fit the best but the slippage is just ridiculous cause it makes it harder for her to get off her forehand or jump. I usually will get off and re adjust if it gets too bad. But Lately I've been over tightening the girth to attemp to keep it in place, its worked some what but its still slipping.
I have a few pictures where it shows how far teh saddle slips.
It slipped a good 2-3 inches or possibly more forward over her shoulders.
Its also effecting her back as you can see this is what her back normally looks like