Okay, I've taken all your advice on:
Helping me to sit at the trot,
Keeping Zorro in the canter,
And slowing/speeding up gaits!
I rode Zorro with a crop sorta agressively the other day. It worked wonders! I was working on my sitting trot, and Zorro's staying-in-the-gait-until-I-told-him-otherwise. So I pretty much perfected my non-bouncing strategy and now Zorro knows he gets smacked with the crop if he refuses to listen to my leg/voice cues. So once we had the trot good, I asked him to canter a few paces, then slow. This worked amazingly and I had him cantering figure-eights!
Anyway, so now I have taught him that rein/leg pressure mean speed up/slow down. He doesnt change gaits now with an "eeeeasy" command from me, it just slows down the gait (if that makes sense?)
Anyways, so I just thought Id update you and thanks you for your amazing advice. I truly think this is now the best horse I've ridden in a LONG time!