MGR recommend you to use Super anyway, which I have for years, so "E5" is the way to go. E10 is not going to do any damage though, as Jeff says.
Incidentally, I think you must have broken a record, Carl. Over 12 years since joining, before your first post !
Do you own a 260? If so, please let us know, and maybe join as a full member; there's lot's of info here once all the sections and threads are 'unlocked' for you.