I would go to nearest thickness gasket, it makes little difference to compression ratio but it allows a bit of insurance against thermal expansion! I do this all the time when i rebuild engines, it’s cheap insurance !
Head is back! The woman who did the work said there was less than 4 thou taken off as the face was amazingly flat. Nothing to suggest any warping whatsoever. im very happy. I can get a full elring headset for £88 inc head gasket itself. I’d like a reinz headset if possible but can’t find one anywhere. Anyone help on this or is the elring a good option?