Have you considered instead going up to a smooth three piece draw gag instead? They are a lot softer, same mouthpiece, but a little more "Hey stupid, I'm still up here" than a snaffle.
I'm not sure what is legal for jumping, but for a strong bitless horse I like a Little S hackamore or a Pozzi hack. Generally both are thought of as barrel racing equipment but I see no difference between a strong barrel horse and a strong jumper, except one comes off the ground and the other gets in it.
Pssh.I didn't pick up the wrong lead
It's called a counter canter...
...A very advanced maneuver.