I also wonder about the age and hours of pa42's belts. I'm not calling you a liar but up until a few years ago when I stopped working on them, they had a life of 500 hrs.
As for the engage time, about 8 seconds give or take a few is what we used and all this told you was whether or not belt tension was adequate.
What happens when you engage the clutch is the belts are stretched because the top sheave is pushed away from the bottom sheave until a PRE DETERMINED tension is reached inside the clutch actuator worm drive assembly. Adjusting the micro switch only changes the amount of time/distance the upper sheave will travel downwards, ie toward the bottom sheave to loosen the belt tension. This then affects the distance to be travelled and the time to get the rotors spinning on the next clutch engagement.
Hope that helps. You can also get a very good idea of belt tension by using the following rule of thumb.
Find the u shaped part on the frame where the belts run past that seems to serve no other purpose than to keep the belts from wobbling. It is just below the top sheave but I can't remember which side. Just under that, using you middle finger, push directly in on the belt. Disengaged, you should be able to push your middle finger in so that the second knuckle sits under the u shaped belt guide.