I did the bit survey... many ride in hackamores of various kinds. I'm not sure I'm up for bitless yet. I did get a chance to watch the Myler videos and they made sense to me. What about one of their gentlest (three jointed, maybe?) snaffles?
You may need to try out several different ones to see which one best suits your horse.
This website: Myler English and Western Bits and Accessories will let you try the bit for 3 weeks for a small fee ($5.00 + shipping). I ordered my Myler from them; I didn't want to be out that much money if my horse didn't like it.
Goodluck in your search!