Avon St 45/46s have been good to us on tours out West. The Ducs are generally about 100 lbs lighter than the Beemers, but almost twice the RwHp. I get about 6k out of one rear on our ST4s. It has been about 2 rears to one front, but here's my stats; 250 lbs, run with both bags chock full, MagsBags U-bag on top of those with all camping gear, and a daypack/backpack set into the middle of the U-bag. The Avons are affordable and great at 9/10s on aggressive canyon runs.
We run either 94 or Hwy 2 out west to the edge of eastern Montana. Last year in a full on downpour we were running with an M3 on the freeway/94. Ran for about 20 minutes at 100-130mph, fully loaded, the Avons didn't squirm. Extremely stable. The wife's bike is fitted with the newer Mez6s.
She runs a '91 K100RS on X-country hauls. So far the 6s have been pretty damn impressive as well. They aren't quite as good for full on race mode but I think their longevity may put them on the ST4s next, if they have a tire to fit, which they should. Running a stable of 7 bikes between 2 people who run a combined mileage of around 40k a year, we change our own tires. More mileage per rear=less bloddy knuckles. Good luck in your shopping and try not to put too much weight on what the mags say. Keep throwing out ?s in the forums.