Roger, you're right that it feels very flimsy.
This is brand new stuff I have here. The pinholes are indeed very tiny (except for one that is not very tiny, just tiny). You need to hold the film right up to a bright lightsource to see the pinholes easily. They are not all over the whole sheet but in several relatively localised areas.
I'll give the filter a go tomorrow if the clouds clear, but I'll invest in a solid glass filter after that. Astro-optical tell me that they can have them custom made for any scope (to fit OTA to the mm), so it's a snug fit. Costs about the same as ready-made ones in fixed sizes.
I think I'll go the custom fit job for the Mak. A 6" scope should be a nice aperture for solar observing... no? I'm thinking the Sun must be plagued by thermal noise more than any other celestial target, so any more resolution than a 6" scope has is not needed...
