When my Mum is riding, she feels as if she is going to go flying because of the horse's tiny shoulders. Would having a thicker, maybe western saddle blanket/pad help? The saddle blanket she has on her at the moment is a very thin Wintec saddle blanket that came with her saddle. We also think that it would be more comfy for her horse if it was thicker. (Since her back bone pokes out a fair bit).
The saddle blanket is the same as this one:
(I found the picture on google)