Regarding VEGASGSA's comments about the inner flange, it's been a while but I'm pretty sure some aftermarket grips I've bought in the past came with a thin plastic ring the same diameter as the flange just to avoid this situation. You just put the ring between the rotating throttle grip flange and the fixed control piece and there was no friction/sticking effect.
Maybe you could just locally make such a ring for your Oury's? (Which I think look really nice).
Current: 2014 R1200GSW