If she moves fine in it, then I wouldn't bother changing.
The reason I, and many others, don't really like it is because of the design. They tried to make a "transition" bit, for when a horse is moving up from a snaffle to a shank. But what happened, since that's impossible, is they created a very sharp bit, that gives confusing, and incorrect cues. You're either in a snaffle, or you're in a curb. There is no inbetween. But there is, different shank lengths.
Because the shanks are so straight, it gives an immediate cue, hence why I called it a sharp bit. A shank that curves a little bit, gives a softer cue to the mouth. There are other bits with straight shanks, but I personally prefer something with a bit of curve to it.
Like I said, some do ok, and those horses are one's who are neck reined, on a very loose rein. It's not correct in the slightest to ride two handed with a tomb thumb. If your horse is ok in it, then leave her in it. No sense in changing things up on her, if she's doing good.
Edit: That bit you posted isn't a true tom thumb, now that I look back at the pic. A true tom thumb will have totally straight shanks. Other bits are being called tom thumbs, even when they are really not the original design. Like, how single joints are being called snaffles, even if it has a seven inch shank. That kinda thing.
"You're just as sane as I am."~Luna Lovegood.
Last edited by DejaVu; 08-11-2011 at 06:46 PM.