I was finally able to get to the range and try out the vertical mount and thumb rest. I really like the c-more mount. My draw height is much more natural, since I am used to 1911s with iron sights.
I shot the thumb rest in the more forward position (muzzle end holes aligned), and ended up moving it back one hole (hammer end holes aligned). I think I will leave it there or maybe even try moving it back one more hole (hanging off one hole on the hammer end). I am still getting used to placing my thumb in the correct spot on the draw, now it has to go somewhere specific.
I had all kinds of fun, discovering problems as well uncovering answers to some curiosity. As much as I hate locktite, I will probably use a little. My mag release button screw backed out and two of my DAA mag pouches had loose screws. Also, I tested the shot impact at a longer distance and found the bullet hitting 6-9" high, which was very counter intuitive. My firing pin also had an interference problem with the hole in the keeper, and was not resetting all the way after a dry fire. I ended up sanding on it to relieve the interference.
Overall, I am very happy with the 90 degree mount and thumb rest. At $165, together, these are two very worth while accessories in my opinion.