Stud Setting Tool Advice Please

Hello everyone, I'm making some little purses with press-stud fastenings. However, I'm having a lot of trouble setting the press studs with a hammer. These are the 4-part studs, with a rounded outside/front stud + outer-rim snap backing and the inner snap + hollow post back. I have bought good quality studs, which come with their own setting tools and I've followed the instructions, but I end up with split and jagged settings, which sometimes won't "snap" because of the damage. I've tried hitting them hard, tapping gently a number of times, turning them round to even out the taps... I have a pair of setting pliers and I tried those instead of the hammer, but they just split the rivet part and crushed it, rather than making a clean and neat crimp (so obviously they are not the right tool for the job). Does anyone have any tips for me, to help me make a better job of this? I've tried so many times and have wasted leather and studs, when they won't snap together. I really expected that practice would improve my technique and results, so I must be doing something wrong. Liz