I am using Sharpmaker for little over a year. In addition to the set I have ultra-fine stones and I am missing coarse. Diamond stones are quite expensive. I tried DMT coarse Dia-Sharp, leaning against flats. Probably I ruined it applying too much force and I was in the search of coarse stones for Sharpmaker again when I saw this thread about a week ago.
Congress Tool is a local company just a few miles away. I send them e-mail, asking if they have a front store to check their stones. The next day I received reply from Mark Froelick, that they dont, but I welcome to stop by and somebody in the office will help me.
I had time to do this in a few days. I was lucky to catch Mark in the doors and explained him my needs. He helped me to find stones, which fit into base well; but if it is little bigger (their tolerances probably large, than on sharpmaker stones) it is possible to remove some material, using coarse benchstone or sandpaper.
I bought 150 and 320 grits ruby and flex. Mark was not sure that ruby is a good choice for me, but I wanted to buy anyway. He suggested to use moldmaster instead and gave me two 240 grit for free (it is good to be local

).
Yesterday I reprofiled my R2. I used all stones dry. Mark recommended using water.
I started with 320 flex, nice stone, but not that fast. I switched to 150 flex and didnt notice much difference. Both stones leaving nice surface and do not shed. I tried 240 moldmaster and 150 ruby. 150 ruby is fastest, but leaving deep marks on the edge, so it took some time to remove it with 320 flex. Moldmaster is good, but probably 150 would be better.
This is my first impression. I like this stones. They made reprofiling much easier.
For future I will use 150 ruby, if I really need it and than 320 flex.
Also some time in future I would to try their res-cut stones and 150 moldmaster. Too many stones to choose from.