I don't have one but how about self stick velcro between the horse and rider?

 

I took a piece of 3/8" rebar ( got it from lowes for under $10) I put the saddle on the horse and drilled 4 small holes so i could run zip ties through the saddle around the spine to hold the saddle in place. I then positioned my headless horseman on the saddle where i wanted him and marked the saddle right below his spine. Drilled a holes in the saddle and ran the 8' rebar through the holes and hammered it into the ground. Then simply zip tied the headless horseman to the rebar. Fast and easy and he stayed in place through 60 mph wind gusts a week ago. I also paint the bottom of the rebar black and you dont even notice it.

 

Thanks! I will try this method. Love the headless horsemen by the way.