Well - personally I would say that provided 1) you view the Pelham as a means of asking for softnesss rather than a means of forcing an "outline", and 2) you're confident that you can feel the difference between a horse working correctly under you and one that is just fooling you by tucking its nose in, then trying your mare in either a Kimblewick or a Pelham won't do any harm. I have to admit that I used to be one of those who objected to Kimblewicks on principle, but that was chiefly because lots of people tend to view them as a sort of lazy alternative to a Pelham in that they can get away with using one rein. But then, lots of people view the Pelham as a lazy alternative to a double, and as I'm now a confirmed Pelham-lover I can't really uphold that particular argument any more <_< Besides which, horses don't seem to have the same preconceived ideas about bitting that we humans do, so if your mare takes to a curb bit, go for it!