Well, if you have identical keyed dops, each one drops exactly onto the keying method at the same depth and angle. Without keyed dops, you need to put the stone in the quill deeply and gradually bring it down to the lap and rotate it to the correct position and lock it in place. One thing that you can do is to put a locked holder on each stone that sets the exact depth into the quill. Getting the stones synchronized to the same rotation isn’t as easy, but if you always return to the Zero index and put the new stone in using the Zero index position to help you set the rotation, you can then go back to the index value for the tier you are cutting and complete the new tier. I am lucky enough to have an indexed quill and haven’t had to worry about getting the stones aligned for many years.