I get pins and needles in the hands sometimes, but have concluded that it is pressure from my jacket rather than vibration.
Raising my shoulders while riding helps. Or is it lowering them? Whatver, a certain amount of moving around and changing my riding position usually sorts it out. BUT this may not be the same as your problem.
For me gloves need to be quite loose; I use silk inner gloves, too. Trouble is, if the gloves are a bit loose, the fingers are probably too long which isn't good.
Well, after finally getting myself organised, I get some muffs (or miffs as I keep calling them) and stuck them on the GT.
10 miles down the road, temperature at around 0 degC and wind speed high and all was going well, even with summer gloves. Then the clutch gave up the ghost and the bike has been in Woolaston ever since.
Ho hum. Maybe I'll get to try them out one day and post a meaningful review....
Has you wife tried heated gloves as made by Gerbing for instance.
I used to suffer from fingertips going white when riding the bike and found that heated gloves sorted the problem out..............and much more pleasant all round in any case.