Tonight the other saddler came out to fit Saga. The problem with my AP boils down to the fact that he's got the dent behind his withers, with means the saddle doesn't make contact there. So when I get into the saddle, my weight pushes it down and forward, causing pressure points. In addition, there are pressure points along the lower edge of the saddle's panels - fortunately not up by the spine, but still not good. The saddle also wiggles around when it's on his back, indicating there's no really good place for it to settle. In addition, the billets don't point in a line to where the girth naturally wants to lie, which is quite a bit further back then usual, about 6-8 inches behind his elbow (you can really see this in our jumping pictures from this weekend, the girth is way far back).
The conclusion is that he needs a medium-wide gullet on a fairly flat-treed saddle. He also needs panels that are dropped a bit to give him the room he needs behind the shoulder. I ended up trying out two saddles: a County Eventer and a Thoroughgood (Thorowgood?). I was very excited about the County because I used to have a County Stabalizer that I LOVED. However, the Eventer was very smooth leather and had no thigh roll, and I just didn't feel secure in it at all. It was also a 17 and I usually ride in a 17.5. Saga, however, thought it was great. His gaits improved dramatically when I put it on him, and it was obvious he felt comfortable in it. I then tried the Thorowgood, but it was a wide gullet and we had to use a Mattes pad with shims to make it work. It was also an 18 inch seat. I felt like I was riding on a big pillow, which wasn't great, but I also had all this tack under my leg (the billets and such), which was annoying. However, the seat was more comfortable than the County and I felt much more secure, although the saddle was obviously too big. Saga, however, didn't like the saddle nearly as much. His gaits just weren't as fluid. It's hard to tell if a smaller gullet would have made a difference, but as the saddle wasn't comfortable for me, it wasn't going to work either.
So, I ended up with wither tracings (I'll see if I can scan them later) and a better idea of the shape of saddle Saga needs. The question is whether I want to look for a different County (the one I tried was fairly old), think about getting a used Borne', or attend the Schleese saddle fitting in June and see about getting a used Schleese. Certainly a new saddle isn't in the budget.