I've been trying to trace air vent grommets for the old Superstar/Imperialstar/Royalstar/Swingstar kits from the 80ies for around two years. TAMA customer service said they can't supply them. As they have an odd diameter - 11 mm - they are hard to replace by other grommets without modifications to the shell. Anybody an idea if there is a source somewhere? Thanks in advance, Thomas