Balance the throttle bodies,
I did mine on Monday night and it seems to have made a difference.
Problem is that the TB's should be balanced at idle but I noticed my front cylinder was always sucking in a higher vacuum and was reading higher on the gauges when revved so also had to adjust the linkage screws, which then upset the idle vacuum, so took a bit of fiddling between the two but got it perfect over all revs.
Don't see the point in setting the TB's at idle when we are getting the vibs at the 4.5k rpm point anyway.
Same thing with the engine bars, they will only magnify any roughness in the engine at those revs, like a tuning fork at a certain resonance, so makes sense to balance the bike across the rev range.
That said you will always get a certain roughness with a V-Twin, called character.
I had a Varadero 100 before and sold it because I was getting numb hands after 300 miles but have ridden over 450 miles a day on the 650 Glee and had no such problem.