Hi Matt!
Dupuytren's diverted a family friend-doctor's career as a surgeon (he's happier in emergency medicine), so I am familiar with it.
My lobster-claw gloves came from Seattle outfitter Early Winters some 35 years ago, and were fitted with knit cuffs, intended to keep runners' hands warm. I removed the cuff and fit gauntlet extensions of knit Gore-tex to match the rest of the "body" -- they've worked well ever since and are now my cold-weather as well as wet-weather gloves. They're fantastic for cold-wet conditions that really chill the fingers. After my frostbite, I really need to wear them whenever I rise in temps below freezing.
As per my comment to Jawine above, while they do a wonderful job breaking the direct wind, your fingers can still chill from direct contact with the cool fabric pushed against them. I wear a conventional fingered under-glove, though a lobster-claw style inner would be more ideal, especially for your needs (I have seen them, but can't pull up a source at the moment). The real beauty of the lobster-claw gloves is they combine the best of both worlds. The last three fingers are packaged together for warmth, while the thumb and first finger are free for fine-motor tasks...like shifting.
I really to think lobster-claws are the ideal item for your needs...plenty of room in that last compartment, and I have on many occasions made a fist in them to exercise and stretch my hands after too long on the handlebars. Plenty of room for that in mine, though I suppose not all are made the same.
Best,
Dan.