In my opinion it is always best to cut the corner beads at a 45* angle so no metal overlaps metal. That way you can also get your corners to touch with no gaps. Also, I would never ever use screws on corner beads. They tend to bend and crinkle if over tightened, it's a bad idea. If you would prefer, you could always use vinyl and a spray adhesive, but also cut the ends of you beads at an angle. I've bee. Doing this a long long time on million dollar custom homes and have never ever used screws in corner beads. Also, crimpers are garbage and I wouldn't trust my corners being installed with them. Nails for metal, spray adhesive for vinyl.