I've seen both 16 and 20 with no ode (as Actually Ed the Undying) and haven't seen anything outside that range.
Edit: some data points (with ode):
16+6=22 adv
18+6=24 adv
19+6=25 adv
KoLmafia thinks a Lucky Lindy gives 2-4 adventures (https://github.com/kolmafia/kolmafia/blob/main/src/data/inebriety.txt#L411) when it now gives 16-20.
To see this, look in Item Manager with Speakeasy access:
KoLmafia r26110