Saddle type for walking horses

[guest@endurance.net]

Tracy Behan ECD@ga.prestige.net
I currently ride a Tennessee Walking Horse and over the past 5 years have
done Limited Distance.  My first and only saddle has been a "take off" of
a Big Horn Endurance saddle. Since my time and lifestyle only permits me
to condition and ultimately ride LD, the saddle seemed to work OK.... I
recently bought a Big Horn endurance saddle and the 5 times that I have
used the saddle in conditioning (3 - 5 hours) each time, the horse has had
a sore back 2 out of the 5.  Those 2 times he was sore were longer
conditioning rides (5 hours).

For anyone out there who rides a walking horse (I know there are not many)
my question is this:  for the amount of time that I can dedicate to
conditioning (one 3 - 5 hour ride per week) to do 3 - 5 LD rides a year
what saddle would be the best for a WALKING HORSE.

Tracy