Well after more "research" I think grease cures one problem and adjustment cures another.
Mine is now, knock on wood, silent, by adjusting the height/angle of the fixed rear glass panel. I did not add any foam/padding as per the video, just adjusted the roof position using the 6 T25 bolts as shown in the video ^. Definitely be careful torquing these, they were not torqued much from factory.
For mine I wound up finding the following to be silent:
* FORWARD part of roof in a roughly MIDDLE position.
* AFT part of root as LOW as possible.
I set mine entirely symmetric from side-to-side.
It actually lines up pretty well with the contour of the roof like this, although the forward (movable) portion of the roof does stick up a tiny bit relative to it when closed. No worse than it was from the factory though.
There's an area paved with "large cobbelstone" at the entrance of my subdivision that serves as a perfect testing ground. Recommend finding one of these and doing laps, pulling over, adjusting roof. Felt like more of a complete idiot than usual doing laps around it, but oh well.
Also ran it through car wash...seal appears to be better, almost no water going through the drain system now (there was more with factory setup).
Very happy for now...really hope it *stays* this way. Posting this 15 minutes after fixing it though, so yet to see if this solution works across temperature ranges.