Bits... damn bits!

So I've been having bit issues with Jasper since I got him in early April. Mainly that he sticks his tongue over the bit and leaves it there. He has a small mouth, very low, flat palate and a huge tongue. When I put a bit in his mouth and get him to stick his tongue under it, his tongue is so thick and his palate is so low the bit sits crammed into his palate by his tongue. He either sticks his tongue on top of it or sucks his tongue back so only the very tip is under the bit.

I've tried regular snaffles (bad), a regular KK (really bad, not sure why other than I think it was waaaaaay too think), 3-piece bits and, well, finally bought a Myler Loose Ring Comfort Snaffle because it was the thinnest bit I could find. That one has been the least bad so far but it's not great. " The Comfort Snaffle features allows the rider to isolate one side of the bit for bending, balancing, and lifting a shoulder. With a special "no-pinch" barrel and curved mouthpiece that applies firm pressure—not pain—on the tongue"
He seems to go OK in it other than his tongue is over it the whole time and every now and then he has these 'freak out' moments where he throws his head down and violently shakes it. It's like he gets pinched or something, although I can't figure out how this bit could possibly pinch. His tongue really does jam it into the roof of his mouth though (when I force it under) and the middle piece looks like it pokes him, especially on the corners.

At Rebecca Farms a great dressage trainer suggested the Sprenger Dynamic RS Loose Ring Snaffle:
It's the newest version of the Sprenger KK. The 'bean' in the middle is turned 45 degrees and the bars are arched. It's supposed to form to the shape of the horse's mouth relieving pressure points and sitting nicely on the tongue. She said she had a horse with the same mouth problems as Jasper and this bit was a miracle. And the cost? $117 plus shipping, of course. Gaaaak!!!

I bought it with some money I earned working overtime. I tried it today. He seemed to go just fine in it, he's had a week off so I didn't push real hard, but he seemed pretty soft. I was excited and got off to see what was going on inside his mouth... and that darn tongue was sitting on top of it as usual.

I've decided I need to teach him how to hold his tongue under the bit. Right? Don't I? I tried the rubber bit port:
This is wrapped around the center of the bit and the depressor is supposed to hold the tongue down. Jasper got his tongue over it, shoved it to the side of his mouth, and chewed it up.

I can try tying his tongue down which I'm a little nervous to do. I've never seen it done and I would hate to do it wrong, or get it too tight.

My other options (as far as I can tell) are these 2 bits, the Tongue Bit:
Or the Spoon Bit:


I like them because they're 3 pieces. I'm not crazy about either of them just because they are pretty thick in comparison to what I've been using. Plus they're not legal for dressage... but my goal would be to teach him to go with his tongue under the bit and then switch back to the Sprenger Ultra.

My last choice is to start riding in a hackamore...

Any suggestions?

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