The flats are because the rollers didnt turn.. stuck in old hard grease maybe... so happen thinner grease is better allowing movement? Did you say you were inspecting yours?.. how many miles on?
I was reading an article that said you should use grease with a high oil bleed for roller bearings but I think that was for bearings that are spinning as opposed to pivoting. By the same token it would perhaps tie in with the thinner grease idea, at the same time i would be inclined to go with Mikeyboy if you could get a brand name, there's no substitute for experience.
Mmmm... just thinking thick grease may tend to hold the needle rollers and stop them rotating?... may be not initialy, but after time as the grease gets even thicker and less liquid... Its a rocking and not a turning action we see at these joints and I fully get the molly thing as that is used for high loads on the splines....
Who knows.... but as you say, mike has seen many so guess he's got the most experiance... What do BMW say?... do they just use std stuff...
And is it worth re-greasing my new INA bearing with something also??