That rhythm is INFECTIOUS.
Join Date: Aug 2001
Location: Pickerington OH
Here's my $0.02:
The cams will stay in position (properly aligned between the dots), in general. I've changed my TB twice, never had a cam flip around on me, but yes, there is a good bit of tension on them.
Only if you end up turning them beyond the alignment marks should you have to worry about it breaking loose on you. But the only time you'd be doing that would be to possibly make an adjustment to the TB fitment, in which case I definitely recommend using a breaker-bar and appropriate socket. Keep a firm grip and you'll be fine. Your leverage on the breaker bar will easily overcome the tension of the valve springs.
My first TB/WP swap was scary as all get-out, had never done any kind of work on an engine like that. I ended up one tooth off on the belt, didn't really notice until a day or two later and it ran rough at idle. Had to tear it all back apart and re-install the belt. Lesson learned - do NOT skip the step where you rotate the crank around a few times to verify that all the dots line up properly after a full rotation.