Crossposting here from the eventing board - I have a very sane OTTB who has an aversion to bits that are “heavy” in his mouth. He goes fine in a Nathe but needs a new one - fairly happy in a hollow mouth snaffle but those are still too fat for his mouth/tongue. In the process of getting his teeth checked.Anyone got bit suggestions??? 
I found that the Neue Schule bits were very light in fact next to my KK it was markedly lighter in weight. Ive been using it for almost a year and it seems to be a very nice quality bit.
http://nsbits.com/
Well, you could always spring for a titanium bit. Those would probably be the lightest metal bits out there. I’ve heard good things about the Lorenzini bits.
If your horse has a very light mouth, you could try a Meroth leather snaffle. I’ve also heard good things about those, but you’ll need to replace them as the mouthpiece wears out. And I’ve also heard (now granted it was one of those friend of a friend of a friend deals) of horses getting rubs on the corners of their mouths from where the leather meets the ring, since the leather wouldn’t slide as freely over metal as metal would. I suppose bit guards would solve that issue though. And I’m also 95% certain they’re competition legal.
The other downside to the Meroth bit is that you can only get it as a loose ring snaffle. Lorenzini bits, AFAIK, come in your standard gamut of mouthpieces and cheekpieces. They also make pelhams, weymouths, and gags. The Meroth bits are, however, cheaper.
ive also heard good things about lorenzini bits
I’ve had a few Lorenzini’s in use for the last 6 months and have been very happy with them.
http://www.theconnectedrider.com/horse-tack/bits/eggbutt-gold-french-mouth-o-link-snaffle-bit-5/
We started carrying the above after our Arabian and T-bred customers asked for a lighter weight bit. These are fabulous, cheek pieces are smaller and more refined too.
I switched out to the Lorenzini bits for my double a couple of months ago. They are shockingly light. I think the whole bridle, bits and all, weighs less than his snaffle bridle & bit.
My only issue with them, and I believe that it is not an unusual issue with the titanium bits is that he is a bit drier in the mouth than he was my old Herm Sprenger bits. I have counteracted this by giving his a couple of sugar cubes just prior to putting his bridle on.
Well titanium is very inert. It’s not surprising that your horse’s mouth is drier. There probably wouldn’t be much taste to the bit, especially compared to sweet iron or something with copper inlays.
Lorenzini is the best. Just FYI tho–if you get the loose ring order one size up on the width. They must measure from a slightly different spot than my sprenger bit. The same size loose ring in the Lorenzini was just a fraction too small with the little hole that can pinch the lip. You will love it and so will your horse. I have a 5.5 18mm center lozenge for sale at $150. $220 new.(the slightly too small one…:-/)
