I would suggest either a windshield or a fairing, I have a fairing on my 2007 and a really short windshield on my 1975. It makes a big difference to get the wind pressure off your chest and it feels a lot more comfortable. This for me reduced the amount of grip I felt necessary on the handlebars and I don't get the tingling anymore.
I rode my 2007 out to Sturgis with no windshield, got lots of tingling, put the fairing on about 3 months later and would never go back. I also have a really short windshield which I was not using. When I bought my 1975 I rode it a few times and decided it was time to put the windshield on and wow, what a difference in comfort. My 2 cents anyway.
Something not discussed yet (that I saw) - if she's got a deathgrip on the bars, the feeling that usually causes that - feeling like you're getting blown off the bike, can be seriously alleviated with a windshield.
Or by getting a seat with a back rest. I have both.
The tingling comes because she has a break in the angle of her wrist. A nerve in her wrist is pinching. Fit the bars to her so she has a flat wrist. Make sure the grips aren't too big for her. Make sure she is sitting the right distance from the bars.
Kinda why you wear a brace to keep your wrist straight with carpel tunnel syndrome. Great point.