Sunil, I think that the tool you described is called a disgorger. I've used them alot and have had really good success with them. I've had times where I couldn't even see how far a little blugill swallowed the hook but the trusty disgorger had him back in the water in a matter of seconds.
What I havn't had so much success with is the circle hooks. I've mostly used them for 1-1.5 lb catfish, but bass and catfish alike they just never seem to have any trouble at all geting hooked way down deep. Of all fish I've caught on circle hooks I've only had 2 get lip hooked. I had far better luck just using regular J hooks and trying to quickly set the hook before they got a chance to swallow it. And if I was too slow I found that the disgorger worked very well with the J hooks but could not be used at all with the circle hooks. Even if hooked in the roof of the mouth it seemed to take half the time to remove the J hook than a circle hook.
Was I using them incorrecly or are small catfish just masters at geting gut hooked?
-Scott
