Hey BB. The one thing I might be able to add to this is that about 2 months ago, the SC circulator pump in my SRT initially became intermittent, and then crapped out altogether. That, of course, made the SC initially engage intermittently, and it quickly went to not engaging at all, due to the higher intake temp. (It went from fully functioning, to intermittent to totally non-functioning in the space of about 15 minutes).

When it was intermittent, the dropping in and out of the power increase SC provides was EXTREMELY noticeable... like when it went out, a Prius would probably have blown my doors off, and that might not even be an exaggeration.
Before I changed the circulator pump, when SC would disengage abruptly at or near full throttle, even my wife said "what the #&(@ was THAT"??? I mean, it felt like I turned the key off, the dropoff was so dramatic.

It certainly SOUNDS like your blower is not engaging when it should, but based on how my car reacted when the pump was out completely, I'd think if the blower is not engaging at all below 3k rpm, the lack of power below 3k would be very obvious.
Measuring the gap with a feeler gauge seems to be of obvious importance, but even Code 3's instructions say "check the gap between the backplate and the clutch. It should be between .20 and .30mm. The important point is that once tightened, the pulley and clutch spin freely of each other, while being as close as possible".

Before I added a shim yesterday, the SC to backplate gap WAS under .20mm, but the SC did spin freely, and I could still stop the SC clutch with my bare hands when the engine was running. Makes me wonder if I really needed the shim at all?? Without the shim, the SC engagement was really smooth and undetectable when driving. It still is now that the shim is in, but it makes me wonder if there would be increased wear or stretching with the pulley springs.
I guess we'd also have to factor in some room to accommodate heat expansion, so who knows??


Anyway, I hope some of this might be of help.