Just in case anyone was keeping up with this, I just got in a bunch of and tried a 9T, with the 46T spur with the bowtie MTRs. It very rarely cogs now, and even when it does, it's no big deal. It only does it for a split second and then goes. Apparently, the MM had a problem with my setup and the heavy truck with the large 40 series tires. Every time I reduced the gear ratio and reduced current draw, the cogging got better.

Perhaps the MM in a truck needs some massaging on 4S to keep the current draw down. I wonder if going with something more than 4S would have fixed the problem.

In any case, I'm going with the Compro. I hope that it will open up some doors to taller gearing.