I like the M1 20w50, used it in the ZRX1200 last riding season. 5,065 miles, sus vis 93.7, tbn 6.4, flashpoint 410, aluminum 24, iron 15.
Aluminum can be from the clutch basket in the shared sump that gives the ZRX it's aluminum number. However I did put pistons in about 12,000 miles ago, so it had been about 7,000 miles after the pistons when I began to run the 20w50. But popular opinion around here says it's from the clutch basket.
Not sure what aluminum may be from in your case, pistons?
This round I went with M1 10w40 4T again. I had run it the oil change previous to the 20w50 as well and had almost identical wear numbers across the board for just under 5,000 miles.