Ahh the clutching debate.
Clutching is very personal as I think we all understand. Personally, I'm not a drag racer which was why I made that little joke. I'm a mountain rider. More than that I like to play in the trees. I'm no Chris Burandt by any means, but I like the technical stuff.
I think what deepdiver is explaining is that track speed (spin) isn't necessarily a true indicator of what your sled is doing. I know alot of people are always looking for that elusive track speed. It has been engrained into our minds that if we are reading higher track speed we must be going higher up the hill. Not necessarily true. This isn't as important as acheiving full shift out of your clutches and
getting the power to the track and keeping it there.
Too steep of a helix may read a good track speed, but what happens when the climb is the toughest. A clutch setup that isn't backshifting properly or getting you in the right gear for the situation can be the difference between stuck in 10 feet or making it over the top in 30.
Clutching needs to start where?
answer: at your primary clutch.
To take full advantage of the gearing available from your clutching you first have to get your primary to transfer as much power as it can to the seconday. To me this means positive low engagement with no belt slip. This is why I'm not a huge fan of the steep initial angle. You are all but throwing your lowest gear in the garbage. Again, this does work to load your motor, but doesn't suit my riding style. Not here to argue either, just explaining the differences.
What is your secondary clutch?
answer: it is a torque converter. This is the more amazing part of the equation. Now that you are transferring the most power from the primary, the torque converter must then send it to the chaincase etc etc...Your secondary has also been referred to as a belt tensioner. Your secondary clutch has to sense when you are under acceleration, when you let off the gas, when you have powder snow, when you are climbing on and on. Not only does it sense what your primary is telling it, but also what the track is telling it.
If you are on that steep climb and running out of juice your secondary needs to say, "hey we should gear down a bit". This is the back shift everyone refers to. Even when track speed is decreasing it is important that your RPM stays very close to peak. This indicates the sled is back shifting properly.
I think we all agree to gear it down. Get the clutching down and the track speed will be there. These sleds love to be around 8250rpm! Sorry, babbling again.