My trainer and I visited a local tack store, and they had a Schleese GP/Jumping saddle on consignment. It is the tree width and seat size that I need. It also has a "Flair" system, which means the panels have air bags in them which can be inflated/deflated to fit the horse. I have heard that these can leak, and the saddle fitter said she can remove the air bags and replace them with wool flocking, which is what I plan to do. In the meantime, I am using the saddle with a thick pad to protect Harley's back, and he seems okay with it. But I'm not quite convinced, and I'm not sure Harley is either.
If you have never had your saddle fitted by your trainer or an expert, I highly recommend that you do so. It is not true that adding saddle pads or shims will make a saddle fit correctly in all cases. Don't find out the hard way, like I did, by being bucked off, that your saddle is hurting your horse's back. A correctly fitting saddle can also correct behavior and performance problems. But always have your horse looked at by your vet first, if you suspect it is reacting to pain of any kind.
We'll let you know what happens with the Schleese.....