any gunslinger build starts with dex. Depending on how you proceed will depend on the rest of your build. If your going for desperado, you'll want int/vit since desperado does consume a great deal of SP and vit so you don't killed when surrounded. You'll also need some agi to to minimize the cool down time between desperado so that you can fire one off after another or else it defeats the whole point. However, most gunslingers start with a basic rapid shower build and evolve from there. Whether it be to a Gatling gun to shotgun, it all starts with dex. The question is, how hard and how fast do you wantta hit?