You can best make the stones identical if you cut them identically tier by tier. If you have a stable Mast (or hand piece), you can do the following: Dop each stone and fully cut the tiers on all stones without changing the mast height for each tier until all the stones have been cut. This is one of the times having keyed dops is a big help. I would do this for all the cutting and pre-polishing of the tiers. Polish each stone separately as this should not change the size for mounting as ear rings.