Thanks for the replies guys, although I guess I'll need to read more about the size of the pinhole to fully understand why that one might be too small. In the meantime, I've gone for a Noon pinhole that uses 120 and can take 6x12, 6x9 or 6x6 shots and I've got plenty of OOD Ilford film to practice with. I'll be back looking for help in the coming weeks.