I attended one of MIke's seminars (workshops) in June 2009. I changed over to much more operation of my TT Pro 500 in continuous mode, versus momentary after attending Mike's seminar. My takeaway was that the immediacy of the momentary setting was really best used for applications right near the handler where you want it to be an immediate snap of a correction and then it's over. But for pretty much all corrections at a distance from the handler, even if you are shooting for a "nick" and not a "burn", you still do it in continuous mode and meter the duration with how long you hold the button down.
As someone else has already mentioned, you can put the collar on a moderate to high setting and "practice" your button timing. As long as your hearing is good, you can audibly detect when the receiver is delivering correction. Just don't touch it to your ear while you're doing it!