Οmega, lots of good advice from oldndumb, philB and Co. in the other thread...
It's a 1200cc twin
we're talking about here, it's gonna vibrate, no 2 ways about it my good man.
I'm with oldndumb, you're just death-gripping the handlebars, vibrations are going to transfer to your hands, i'm not sure exactly what you're trying to "troubleshoot" here.
How's your riding position/posture ? are you cracking your elbows like you should (at high speeds) ? Are you relaxed while riding or are you giving the handlebars the death-grip ? What's your age ? Do you exercise ?
kind of difficult to do a...tele-diagnosis but...judging by the other thread you opened and this one here methinks it's a just the good ol' case of the death-grip, now, taking into account that this is also a big 1200 L-twin motor we're talking about and...yeah, no surprises there (regarding the vibrations).
If this is your first L-twin (which i think it is from what you mentioned in your other topic), well, you're not the first one to complain about vibrations
Personally, after having ridden my previous air-cooled 2V Duc for thousands of miles the M1200 feels like...a limousine, i kid you not friend, you can't even begin to imagine the difference between the "feel" of the air-cooled 2V motor and this newer liquid-cooled 4V one, it's like...night and day, thank God you didn't buy a 696/796/1100 'cause, yeah, the vibrations at lower RPM's especially would have murdered your hands...and feet...
On a more serious tone, try some gel-grips, try to stay relaxed on the bike, don't death-grip the bars and report back with your findings .