Heavyweight saddle preference?

["brenda casebeer" <casbeer@molalla.net>]

Hi everyone, I wanted to ask some of the heavyweight riders what 
they're saddle preferences are.  I've moved my two geldings up to 50's 
this year, and both of them have developed sore shoulders just below 
the withers--complete with white hair growing in, and are vetting in 
with B's on back soreness.  

I have used the Big Horn endurance saddle, a well fit close contact 
english saddle, and an Ortho-flex.  Have used skito, wool, 
neoprene and  coolback pads.

I come from a dressage/hunt seat riding background, try to ride 
balanced and light, and have had people watch me ride and don't think 
my riding is the problem.

Is back soreness a common problem with heavyweight riders?  Is the 
increased time and distance in the saddle fatiguing muscles to the 
point where the horse is going to be sore no matter what?

Horse #1  5 yr Polish arab gelding, 15.1H stocky build  2 yrs of LSD
Horse #2  6 yr Appy/Arab gelding, 15.3H fairly substantial, 1st yr of 
endurance

I would appreciate any input/suggestions!

Brenda Casebeer
Molalla, OR