The big, coarse stone came a couple of days ago, but I haven't had a chance to try it on an edge yet. It is Big, and I recognized it from rub "bricks" for tile work. It is nice, and flat on all surfaces.
I was looking through Bon Tools stonework tools, and ran across their selection of rub stones. Those are only 6" x2", but I ordered a 24 grit, and a 46 grit, mainly to see what they will do to a beat up chisel. If they are way too coarse, I'll use them sometime for their intended purpose.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1