Regarding the interference on your horse; I had that problem with my Duke
horse. He was a very narrow horse and would interfere in back - making
nicks on his back fetlocks. My farrier and I worked on this problem
together. We kept records and discussed any possibility we could think
of. (Thank God for a farrier with an open mind). With logic & study we
discovered that the "side-to-side" angle needed adjusted. I haven't seen
anyone discuss this but it is just as critical to a horse's travel and
balance as heel to toe angles. By dropping the outside a tiny bit, we
eliminated the problem and Duke travelled smoother. He had to be
re-shod every 3-4 weeks to maintain proper balance. Hope this helps;
they are all different and I've never had another horse requiring this
type of "correction."
Sunny trails,
Diana Benson