Good advise, I don't use the gasket punch kit very often and didn't at work much either (I used to repair train electronics, occasionally a new case seal or some custom mica insulators needed making).
I've now made some more of the carb gaskets, without cutting them out before punching the holes. I was previously using a piece of chipboard that came in the packaging of a well known flatpack bookcase. I've now found another piece as the other one was rather worn out from punching cylinder & induction gaskets.
Here are some from the batch I have made, with a third sheet of thinner gasket paper to get the correct thickness to match the original pair of red gaskets used between the induction housing & carb. I haven't checked yet but the thinner one maybe similar to the single gasket used on the early O&R engines.
David