I've got a Supracor oversized pad that works GREAT!   It's for my reining saddle (dale martin custom) which is too nice for trail rides (I'm broke and poor but my horses live very, very comfortably).

I use a wool navajo under the Supracor so it will last longer.  With my reining saddle on top of the supercore, I can get my hand under the saddle & pad effortlessly even around the withers.  My horse sweats evenly and it's super comfy.   NO pinch points, even with other saddles. 

I'll get another one for my barrel saddle (also my 'trail' saddle) some day.

I swear by Supracor

I also like the dixie midnight.  I lay a Woolor Acrylic Navajo blanket over it.

They allow the sweat to run down the side of the horse and not into the blankets.

I don't need to wash my other blankets very often.

The horses back stays cooler.  Now if I could just find them in colors other than Midnight blue.

Thanks for the pointers... I had experienced help in picking and fitting a saddle, so I sure hope that saddle fits well.  It is a few inches longer than my other saddle (a very small barrel saddle) so I imagine I am sitting in a slightly different place on his back. The blanket I borrowed was thick, but squashed down in some spots and too long for him.  I brushed it up a lot before using it, but obviously it wasn't enough.  It was a 32" and the back of the blanket hit him right where his hip rises up. That was a sore spot for him. Another factor was that he hasn't been on an 8 hour ride until Sunday, and we did some serious climbing (3500' elevation gain) and then had to come back down.  There were numerous leaps up and down, about 2' high, of rock ledges, roots, etc and that caused him to use every muscle he had available.  He wouldn't drink from the streams which couldn't have helped his muscle soreness.  I rested him every so often, let him graze a while and we even led them down for about 1/2 hour a couple different times, to give them a break.  We had to keep moving so we got down off the mountain before dark.  I posted pics on the camp and trail thread if you care to see where we went.  I will look into the 2 brands of blankets mentioned and see which one I like.  He is fine today, no soreness at all which is a relief.  He is a very very sensitive horse, and sometimes it's hard to tell if he's really hurt or over-reacting.  When he gets his shots, you can't touch him for a few days, especially on his neck.  He gets so grumpy!  You can't use a medium or stiff brush on him either. 

A lot of sore backs are not from bad pads.

Some horses get excited. They get their head up and hollow out their back. This causes even a good fitting saddle to bridge across the back. Causing sore loin muscles.

Watch your horse during the ride. see if he is relaxed and staying collected.

My grey gelding is joy to ride alone or with my daughters on his herd mates. But take him to a CTR where there are 50 other horses and he gets all wound up.  Head held high, back hollow and I guarantee he will be sore after the ride.

I would really investigate saddle fit more.  So much back pain is caused from a poor fitting saddle.

Unfortunately, there are MANY saddle fitting "experts" who really don't have a clue.  Another factor to consider is that just because a saddle "fits" doesn't mean it "SUITS" the horse.

No saddle pad or blanket in the world will fix an ill fitting saddle.  Often, they make them worse.