How flexible are the deb sibley saddles?  I see some are marked panther canyon, some are honey creek.  Are they on the same flex tree, just different makers?

Panther Canyon and Honey Creek are the same saddle company, same owner. The reason the Name has changed is because one partner of the saddle company pased away and the other partner took full reins of the company and decided to change the name of it since he is the soul owner of the company now.

They flex, I dont know how to explain how they flex but they are flex able, they form to your horses back. 

Would it be comparable to just b natural as far as the flexion?   But not bob marshall flexible? 

Nothing like the Bob Marshall, Bob Marshall is Treeless the Deb Sibley is a Treed saddle with the Ultra Flex tree. 

I have ridden in them since 2007. The are definetely flexible but not like a treeless. You can definetely feel your horse more than you can in a treed saddle but not quite as bareback of a feel as a treeless if that makes sense. 

Fairly comparable to just be natural.   I love mine!  I have a horse with one shoulder bigger than the other ~ it takes a few rides, but now the front of my saddle resembles my horse with one side flaring out more.    They have to warm up to mold to the horse.