Hi Lawson;

I run into similar quandaries often enough to have become fearless at modifying existing products to better suit my intentions, or at times start from scratch. It's not exactly the most frugal way to go around; but you get what you want. (Full disclosure: It's not always worth it)

There may be an outside chance of finding very used stones. If you ask in the right places maybe someone would pop up willing to pro-rate. If they have very thin stones; they'll be needing new ones soon enough; 'cause once they get thin-thin they are easily broken