X-Change gullet system? Adjustable trees?

Sigh. So the lovely Devoucoux I bought last summer to fit new horseling puts me in awful chair seat due to too-far-forward stirrup bars. Horsey is being sold and saddle is soon to follow...
So, speak to me about saddles with the X-Change system. Does it work, does it generally help one saddle fit a wide range of horses and really work well for each horse? What about the adjustable trees available for Prestige and Schleese saddles? (I'll probably wait to buy a new saddle until a new horse comes along...but I'm wondering about these adjustable options in case I break down and decide to buy a new saddle first.)
TIA!

If you're willing to "fit" with risers & pads, then one saddle can be used on a number of horses - especially if you're a nicely balanced, light rider & you're just riding the horse occasionally (with the riser, padded, what-have-you saddle) ...
If you talk to the manufacturers, none of the adjustable saddles are meant to be used on horse A for 1 ride, then adjusted to horse B for a ride, then adjusted back to horse A's gullet etc for horse C's ride, then adjusted again for horse D's ride - all of this will start to wear very heavily on your saddle tree & fittings & leather/synthetic (& your tree may break & you'll find out that the warranty was voided by all that adjusting).

Oddly there are some trees/saddles out there that just seem to fit alot of horses surprisingly well (despite not having exchangeable gullet plates or 'dial-a-fit' gullets).

If you're leasing/riding you can also just look for certain horse types that WILL fit the nice saddle you have.

As Alto said, the adjustable tree is not really meant to be changed frequently as a way of fitting several different horses. I have a Pessoa XCH now because my pony is coming back from a long layoff following Major surgery, and her shape is significantly different from what it will be when she gets back in shape. However, the screws that are used to change the gullet go into plastic fittings, which most certainly would not hold up to multiple changes.