Please check out this website. The lady is an accomplished Paralympian dressage rider and has had her saddle adapted with 'pockets' that her stumps are in while riding.

angelika-traberte.handicap-info.de/

Be careful with any kind of adaptation that fastens the rider to the horse. In case of emergency, it's usually better to get off/away from the horse than to be connected. I think the pockets help this woman balance and give security, but she would be able to slide out of them if needed.

She's very nice and will probably answer any questions you have via email.

Hope that helps!

Ann
RAK amputee, Michigan
Western/Trail riding
Spotted Draft Horses