There's a tailwheel "differences training" endorsement for SEP and I think SLMG, but not microlights. It generally takes about 90-120 minutes, although I've seen the occasional club advertise 5 hour courses, which suggests to me either they're profiteering, or regularly getting some seriously inept students.
Personally I count taildragger experience as any hours I have in an aeroplane with a tailwheel or skid, and use a spare column in my logbook to tot them up in case anybody ever asks - which has happened occasionally if looking to fly somebody else's old aeroplane (and I'd ask the same if somebody wanted to fly mine).
G