Overtime, in the sense of more than the normal number of hours per day or week, is usually covered by state labor laws. A shift premium for a normal number of hours worked at other than normal daytime hours or on holidays is usually a matter for negotiation (or collective bargaining, as the case may be.)
a rule of thumb is how most labor unions do it....
not saying it's right, but it's what gets negotiated.
the following, while not universal, is fairly typical.
day shift = 100% jw wage
second shift = 110% jw wage
graveyard = 115% and you get paid 8 for 7 hours work, or
whenever the day shift shows up.
overtime is 1.5x hourly rate for anything in excess of 8 hours per day or shift.
overtime rate continues uninterrupted until you get 8 hours off.
a shift must be 40 hours, to prevent abuse of this, circumventing
legal overtime with "shift" work.