That is some serious coin for those mitts to keep your meat grabbers warm! They are an updated or military branded AltiMitt which is an outstanding mitt but still very costly. I had good success with the Alti but I preferred the Black Diamond mitt, half cost and near as warm. With synthetic filled mitts, the insulation is very slick and the fibers tend to slide on each other with ease. This can cause difficulty gripping items wearing the mitts as the insulation slides around in the mitt while trying to grip and hold on to something. A removable pile/wool mitt inside just a shell is what I prefer and in my experience worked the best for me.
At what temps do you shoot or would use mitts like these? You comment that your hands get cold very quickly, just how so?
A trigger finger, "lobster mitts" sounds good but to use on a trigger but there is a good amount of material to feel through on the trigger. Since your index finger is solo in the mitt, it can get chilled more easily so I suggest when in use, you pull your trigger finger inside the main body so the individual fingers can support each other for more warm. In my experience the separate finger on a mitt is useless.
Velcro in the arctic can be poor at best if the fingers get a little liquid in them to freeze. I have that t shirt many times. Its great invention but not so great in the arctic. Snaps too but metal snaps can take a quick blast from a Bic lighter, stove, etc to unfreeze and work. I have had plastic buckles crack too.
Since you comment you get cold hands quickly, I suggest you take a baby aspirin or garlic pills daily to help with blood circulation. Stay and get well hydrated. Eat small high calorie snacks during the day. Do 25-50 jumping jacks as you leave for the day in the cold to boost circulation, not in the warm house but in the cold. Exercise regularly to boost your metabolism and circulation.
There way too many gloves out there to go over but my favorite pair are CloudVeil, softshell outer with goat skin palm and fingers insulated with 100wgt fleece and foam backing that added insulation but also guarded against contact with cold. Almost all glove companies make something close to these original softshell type gloves from CloudVeil, check out the Vert glove from OR. For mitts check out Black Diamond Mercury and Absolute mitts and their pilot gloves.
good luck, hope this helps