I got some Sig Glass Cloth from Sig Manufacturing Co. at Bill's recommendation. I got SIGGF003 Light Wt and it has worked out well for many splices and reinforced body areas. I may not be doing it exactly to his specifications but I typically apply a layer of epoxy over the joint then lay a piece of fiberglass over it. I'll press it into the epoxy with toothpicks or other object until it's buried. The one sheet I got will last me the rest of my life.
I used to take my Porsches to a Jaguar place that raced and did a lot of customer race car work. They always had old Jags and always an engine sitting all alone ... I would always stop to gaze over that amazing piece of art!