I got a replacement ground glass in the mail yesterday from Steve Hopf, who is well-recommended in um ground glass making circles.

Initially there was a sizing issue with an early one he had sent and me lacking glass cutting tools I asked him for a replacement with correct measurements and he obliged. You can find him on that auction site or on Facebook. This new one fit just fine onto the back of my Pacemaker Speed Graphic and instantly there is a big difference between what I was seeing before and now (plus the old one is in a landfill after my accident).

Just for my notes: the ground glass for the Pacemaker Speed Graphic measures 122mm x 100mm.