Tom Thumb bits and curb chains

["guest@endurance.net" <guest@endurance.net>]

Lysane Cree lysanec@yahoo.ca
I was reading through the FAQ section on bits and bridles 
and read the post that says that there are "some western curb bits which are designed so that double reins can be used. If you have your curb chain hooked to that ring that is even to the mouthpiece it is wrong. This is for a snaffle rein." So where then, should the curb chain be hooked? Or should it be removed completely when using the snaffle rein? Or not used at all, even when the rein is on the shank?
I am currently using a Tom Thumb bit. I know that it is often used by western riders and my horse has almost always been ridden in this bit. And while the bit is usually referred to as a snaffle, it does have shanks like a curb and has a similar effect. At the time i bought my horse I continued to ride him in a Tom Thumb because he responds well in it and I like the fact that I can switch from neck rein to direct rein quite easily if I need to. The bit I have has a copper mouthpiece and the way the bit is made allows the shanks to move independently of one another when you are applying pressure to only one rein. My curb chain is attached to the ring which is near the mouth and my reins to the end of the shanks. The bit hangs parallel to the horse's mouth when no pressure is applied and rotates to perpendicular with horse's mouth when pressure is applied. When the bit is perpendicular the curb chain is in contact with my horse. And I don't ride in a very loose nor very tight curb chain. I had never heard that this would be an incorrect way of doing things, so this is why I was surprised when I read the post mentioned above.
Any insights will be appreciated.
Lysane