Oh my. I like & can appreciate the work that goes into that. I used to build wind powered whirlygigs and know well the intricacies of all the linkages and bell cranks needed to transition from rotary motion to reciprocating motion.
That looks good too, but you better move that young cowboy up some. He's going to turn into a rocket sitting that far back off the bull's shoulders.
Don't ask how I know that....
Any chance you could post a picture of the underside..the 'working parts'?
Do you sell them? If so, how big are they....something that can easily be shipped?
PM me if you wish.
He actually fits nice and snugly with his feet in front of the fulcrum, but then he is more stable- just like you say, Greybeard. When he sits here, you should see him move about!