saddle fit

Question
My horses are all having 6" by 6" triangles of dry areas over the wither area after
a hard work out that makes a uniform sweat under the rest of the saddle. Is the
tree too narrow? OR do I have the girth too tight ? OR do I just ride with my
weight that far forward. (I ride in two point a lot).

Answer
Dear Diane,
A dry spot is usually indicative of a tree that is too wide, not too narrow. It indicates a pressure point where the tree is sitting down, not being supported above, the horse.
Any time I hear a person indicate that he/she is riding multiple horses in the same saddle- it is likely that the saddle may fit one- or possibly two of those horses but probably not all of them. Some people may suggest that you purchase pads and fancy orthopedics but they will no more make a saddle fit a horse than fancy socks will make a pair of too big or too small shoes fit your own feet.
Riding in two point should not compress a correctly fitted saddle tree down onto your horse's back. Jumpers spend most of their in the saddle time in two point. A tight girth will not pull a correctly fitted tree down onto your horse's back.
If you don't have a qualified saddle fitter in your area- you can go to an art supply or drafting supply store and purchase a flexible rule (it looks like a ruler that bends) to give you a shortcut answer.  Place the flex rule across your horse's withers, fitting it to the shape of your horse. Then turn your saddle upside down and fit the ruler into the underside of the pommel of your saddle. If it doesn't fit at all- your horse is wider than the saddle, if it fits leaving room on either side- your horse is narrower than the saddle.
This does not replace a proper saddle fitting.
I hope this helps.
S. Evans