I had a Reinsman Flex tree saddle about a year ago. I sold it because it killed my back! It was also rolly and insecure on my horse. The gal I sold it to loves it though, so maybe it's just me.
The Reinsman Flex tree was a different technology from the RB Auto Adjust flex tree though. I believe the entire saddle bars flexed on the Reinsman, similar to the Circle Y flex trees.
The drawing of the RB Auto Adjust tree reminds me more of an Ortho Flex style, with flexing panels.
Sorry I couldn't be of more help. I guess I just posted to let you know my experiment with a flex tree saddle left me going back to regular treed saddles. I ended up sending a wither tracing to a saddle company and had them match my horse's wither shape to a saddle tree that they had in stock. It has worked out great and no more white hairs on my horse after a long summer of trail riding last year. We did 5 hour rides, about 5 days a week, and I only had one horse to ride. So I'm very happy! So that is what I would recommend. It's not fool-proof, but at least it's an educated guess.