Bitting advice for a fussy mouth horse

[Charglaz]

Help!!
My horse of two years has always been mouthy.
He chews everything; lead ropes, rugs, walls etc!!
He also chews and chomps his bit all the time.
He falls behind the contact and the vertical, causing tension through his backand so does not work Correctly.
He has his teeth done regularly, saddler is also a regular, his back is better than its been for ages and he has regular Physio.
He starts chewing his bit as soon as its in his mouth and there's no pattern to it worsening or improving.
im working on him working into the contact as much as poss.
I've tried:
Egg but single joint
Happy mouth full cheek straight bar and with lozenge
Mullen comfort snaffle
Normal full cheek French link snaffle
Sweet iron loose ring snaffle with copper lozenge
Egg butt Curved mouth piece- no joint
Micklem bridle
Cavesson noseband normal/ loose
Flash noseband normal/ loose
Micklem noseband normal/ loose

I feel he needs something secure with minimal tongue/ bar pressure.
He's better with a thinner mouth piece

Any suggestions of bits would be greatly received ☺️☺️☺️

 

[Pearlsasinger]

NS make a choice of bit thicknesses, with a variety of mouthpieces. If your horse were mine, I think I would start by raising the bit one hole at each side.

 

[blitznbobs]

Ns team up with very still hands!

 

[Lanky Loll]

Hanging cheek French link stopped my chompy youngster. Sits nice and still in the mouth