When you are caping a weld you should always start at the bottom with your first stringer and weld uphill. It’s very important to make your first stringer as straight and consistent as possible. To do this you should leave the edge of the bevel visible so you have a straight line to follow or you can file a line on it. Just as long as you have a line to guide you and keep you straight. If you mess up grind it out and fix it before you move on because the first stringer will be more visible than the ones between the top and bottom stringers. After you are happy with the first stringer then use it as a guide for the next one. Then that one for a guide for the next one and so on. You should stack your stringers tight together lapping them about 50 percent over each other. When you get to the top (last) stringer angle your rod upwards a little bit to prevent undercut. Concentrate on no undercut and being straight as this stringer will be very visible like the first one.