You may consider going to a western fender to decrease
the pressure by spreading it out over a larger area. My International came
with a short leather tube that covered the buckle (with the buckle placed next
to the stirrup). This stopped irritation from the buckle.
Jonni's idea to move the leather/fender forward/back is
a really great idea. When I had the stirrup forward I not
only got shin pressure, I also got really sore hamstrings from trying
to get my leg underneath me to post the trot.
It is very frustrating when the saddle fits the horse,
but causes problems for the rider! My current saddle has stitching in the
seat to keep the padding in place. However, in spite of the comfort the
padding provides the stitching can cause pitching of the delicate upper inner
thigh skin when I ride in thin summer weight tights (of course my favorite
summer tights). I may have to ride in a full seat tight and sweat,
drink and pee more. That will be some time in the future as it seems like
it will never stop raining here in Elfin Forest! Good luck and happy
trails,