We use a bitless sidepull on Stiffler, Amarea's old horse (Tracie's horse now.) He has a very low, soft palate. He was originally being ridden in a Doc Bristol french link and reacted to it with quite a lot of pain. I found, for Stiffler's case, ANY jointed bit caused him a good deal of discomfort and he rode with his head in the air even when there was nothing but the weight of the reins on the bit. I never found a mullen mouth I liked while we were looking, though I would think this would be something he could respond well to, and riding him bitless became the habit, since he responds fine with it. Just wanted to share our experience, french links are often the "go-to" bit for mouth troubles, but it didn't work out well at all for our low-palated horse.
ETA: We also use a bitless sidepull on my mare Freyja (we initially used it on Stiffler before ordering his own to see how he responded) however in Freyja's case it is used due to a metal allergy.
Last edited by Indyhorse; 09-20-2010 at 10:44 AM.