Bit Fail

I am a little frustrated with the world's most awesome pony. While I adore Speedy and am grateful to have such a Steady Eddy, I am beginning to wonder if he has reached his full potential.

My current favorite photo. Yeah, I know you've seen it ... a lot, but it makes me smile. Photo by Gordon Walter.

He now has a "go" button installed, but everything else has gone to hell. In an effort to teach him to listen to my leg, I quit wearing spurs because he had learned to ignore them. He now listens to my leg for forward, but he has lost any bit of suppleness through his poll and back. The lateral work, never great to begin with, now only comes if I whack him with the whip. 

He has also gotten pretty heavy in my hand, so I thought I should change his bit to something with more tongue relief. After all, that worked miracles with Izzy. HAHAHAHAHAHA. Nope.

The wide low ported Myler - dressage legal.

I tried Izzy's as of yet unused wide low ported bit with loose rings. It was a complete and total disaster. Speedy braced his neck and locked his jaw around that bit. I had no brakes and could not get a single lightened stride from him. The "go" was still there, but the lateral work was even worse.

This weekend is the CDS Adult Amateur Clinic with Hilda Gurney serving as the clinician. I am really hoping that she can help me figure this thing out. Does Speedy just need more time to build strength for the new level of collection that I am expecting? Has he simply reached his maximum ability level? Are my aids that unclear?

​Looking for answers, hoping for results!