The good news is that KAT liked my new pad and that it successfully kept my saddle from sliding back. I also learned to make sure the saddle is centered before I cinch because once it's tight there's no "weight shifting" to re-center it once you're in the saddle. That Tacky stuff works!
The pad seems to make the saddle fit better because it lifts it off of the wide part of his shoulder and up onto his pointy withers..... which leads me to the BAD news:
It looks like I need a new saddle. KAT could easily feel what I felt, that the tree was very tight against his back. We put her new Billy Cook saddle (FAIRLY certain it's FQH) on and there was a noticeable difference. Now, my saddle was much better with the pad, but we'll have to see what happens when that pad gets worn a bit and shapes itself to his back. I'm not going to rush out and buy a new saddle since it doesn't seem to be bothering him and the pad is helping, but I'll be keeping my eye out and when I shop for my new show saddle I'll be looking for one with full quarter horse bars.
While we were at it, I put my crappy old ugly black All-Purpose English saddle on him. The saddle fit fine, but the girth was SEVERAL inches away from even touching the bottom of the flap on the onside, while on the last hole on the off side. This just solidifies my decision to sell the saddle for whatever I can get for it. I'm not going to buy a new girth for this saddle. It would have to be black and then I'd have two black girths I don't need/can't use when I buy a new saddle. So I guess I'll put it back on Craigslist and see what I can get.
My ride was pretty good tonight. It was a busy arena again so he took a while to settle into the work but by the end of the ride we were jogging around on a draped rein with a flat neck, doing little figure eights with leg cues. Can't do that at the lope yet, still need lots of checking and shoulder aid.
I have a lesson tomorrow night, so that'll be nice. Wanna buy a saddle? :)