I've used MTB V-brake pads in road dual pivot calipers. I also have a Langster, and used V-brake ads on the stock brakes. Once you get them to fit, which is a tight squeeze, if you don't toe-out the pads, a fair bit, they will SQUEAL. If I recall correctly, some/most v-brake pads will be too long in the back, to clear your fork blades. Unless you add a spacer/washer on the brake bolt, where the brake bolts onto the fork, at the crown, to create the space/clearance for the longer pad.
IF you do decide to go this route, on what I am assuming is a stock Langster fork, and its brake. I have successfully fit a v-brake pad from Shimano's BR-R550 cantilever brake. They only fit because they were shorter in the back, than the front. ie: almost equally long at the front as they are in the back. You'll have to experiment, to find the right pad, or just add a spacer. But I feel that would only make your brakes squeel/flex more.
BUT you do get noticeably MORE braking power with V-brake pads. You will probably have to toe your pads out/in, to keep them quiet.