This is not crazy at all, lots of people own saddles or want their own saddle that don't own horses.
There are two ways to go - one, buy a saddle with an adjustable gullet. This doesn't solve all saddle fit problems, but tree and gullet width are a big components of saddle fit.
I'm not familiar with the Wintecs you mentioned, so don't know if either of them have the adjustable gullet. I would also recommend reading some reviews of them.
The other way to approach the problem is to buy a wide tree saddle or a tree that's likely to fit the majority of horses you ride (meaning medium tree with high wither clearance if you're riding a lot of TBs, wide for most QHs or draft crosses) and then pad it to fit the variety of horses you might be riding. Not perfect, but doable.
I would also say that the liklihood of the saddle you buy now fitting a horse you might buy later is not terribly high, but if what you're after is something comfortable that fits you for right now, go ahead and do it.
Last edited by maura; 01-31-2012 at 10:09 AM.