Join Date: Sep 2010
Location: Ontario, Canada
How long have you been riding/doing the exercises? It does take time to develop heel depth, some people get it right away, some it's natural and others have to really work hard for it.
How long are you "standing" in your stirrups for? My instructor used to make me do long sessions of just standing while trotting to help with my leg position and heel.
Hard to assume this, but perhaps you are "gripping" with your legs too much, not allowing your weight to sink down into your heels. Try doing some no stirrup work as well to help keep the weight down.
All in all, it will come, it just takes time, patience and practice. Good luck...and welcome to the forum!!
"No hour of life is wasted that is spent in the saddle ~ Winston Churchill"