Having done this for quite a few years my advice is that once you get
past the basic arithmetic of people-hour-equivalents etc what you need
is a middle manager who is a good "horse trader" because it quickly
becomes a market of "I can do grave shift Tuesday if you'll take my
Saturday AM, I've got a wedding I have to be at, XXX says he'll take
your Friday night if you take the Saturday but if you still want
Sunday off you're going to have to find someone to cover that and
Monday morning unless..."
And that manager has to be responsible so such shuffling really ends
up with necessary coverage because people make mistakes, often in
their favor (OOPS!), and that can get complicated.
Regular-hours life goes on despite peoples' shifts and they're forever
having to be at jury duty, doctor's appointments, social engagements,
govt offices, religion, dog kennels, kids' school meetings, etc etc
etc which are fixed in the assumption that people work roughly 9AM-5PM
M-F. Yeah some of that is actually easier for people who work odd
hours and even the attraction of odd hour work but a lot of it isn't
and comes up only once in a while per employee which means, for the
manager, once or twice a week.
Another practicality is policies about people "hanging out" during
non-work hours because you'll find overnight people are night people
even on their days off and often have nothing better to do than come
in and use your higher bandwidth etc, or just get out of the house,
they'll become friendly with overnight co-workers, which might be fine
by itself until someone brings in a couple of six-packs because hey
they're not working and there won't be a boss around after 1AM
and...again, maybe not a problem until they decide to share their fun
a little too much with people on duty who are nearby...
The other problem is food, overnight people get hungry and depending
on location and facilities for bringing and preparing food
opportunities for a 3AM lunch can be limited in many locations and if
you don't solve it somewhat employees may come up with suboptimal
solutions like deciding it's only fair that they get an extra 20
minutes travel each way for an hour lunch, or cooking mess, etc.
And of course who to call when something goes very wrong at 4AM or
they'll call you every time, for some value of "you", or worse they'll
call the police (for example) when you prefer they hadn't (or the
police or other LEO will call them)...you need some procedures and
training to anticipate such things, power problems, building
management calling at 5AM that they need whoever is on to let some
people in to knock down all the walls, they're waiting outside...
Finally, a weird thing? If there's overnight telephone support people
(some of whom are customers!) will find it, sometimes lonely people
who want to hear a human voice at 4AM and sometimes completely crazy
people who, well, want to hear a human voice at 4AM, some of them are
very good at manipulating whoever will answer the phone, "our little
secret please don't hang up please don't hang up really please!", you
need policies and training if that's a possibility. Gak, I could tell