This makes sense to me, in fact its just what I did. And buying a saddle is not a lifetime commitment, OP can always sell it down the road if it doesn’t work out and she finds something that works better for her needs. Or have more than one saddle if she’s riding lots of different horses. My trainer had a Butet and a Devoucoux, between the two of them something usually fit but most often she ended up riding in the horse’s own saddle if they had a custom fitted one.
I have a Tad Coffin TC2 with SmartRide tree, and while it doesn’t fit everything perfectly, I have been able to make it work for all my horses (with the help of various half pads). And they all love it. I bought mine used, so it wasn’t that expensive. I used to have 4 jump saddles, but eventually I sold everything but the TC2 so in the long run it was a money saver.
Just a point about the Bates Easy-Change gullets: they take a fair amount of work to switch–not something you would want to do routinely, e.g. in between riding two differently-shaped horses the same day.
I have noticed that a lot of the French saddles on MW trees without a lot of custom paneling will fit most h/j type horses fairly well will minor modifications. My Devoucoux fits my WB like a glove and requires minimal shimming on the other horses I ride (QH, TB, other WBs) to be acceptable.