analogs for currently time markers:

second - muk, where muk = 10 billions oscillations of Cs-133
minute - 100 muk, or getomuk
hour - 100 getomuk, or 1 mikimuk
day - 10 mikimuk, or petamuk
year - 100 petamuk = timimuk

not based on something except logic. doesnt need optimization because doesnt have time leaks - no Sun-/Moon-/stars-/rotating-based time marks