That's what all the great saddle makers say, isn't it, that (in relation to the horse) their 'RTW' saddles fit most, if not all kinds of horses. That the art of the saddle making is such that the saddle accomodates the different stages of back musculature from the young to the trained horse.
I 'only' have Passier GG as a dressage saddle and find this to be true. The saddle fits ME (i.e. my big butt
) and I can use it on any horse I ride. Since I don't ride ponies or small, wiry TBs, this saddle works great on all horses that are big enough to fit me. I have the withers part cut high because most of the horses that I ride have high withers, so that works great too.
I always thought that the 'custom-made' aspect relates to the horse - but was told that this is counter-productive as the horse changes his back muscles with the different stages of training and work he is in. I now understand a 'custom-made' aspect to relate to the rider, i.e. if you are very slim and have very long legs, or the opposite, how you want your knee blocks placed, etc.
Liza, I think your Courbette should be A-OK, given that it has enough stuffing and that the tree isn't broken or anything.