If the loyalty loss for a unit of a single man is on the order of 5
points/month, then even a loyalty 60 unit would make it almost a year
on his own. That seems reasonable to me. And of course you could
always "pump him up" ahead of time to 100, in which case he'd make it
for a year and a half.
The more interesting question is, how do you get a complete separate
"subset" of your faction established somewhere? Since all units lose
loyalty except the PC, it would seem to be impossible to have a
completely independent sub-faction. The answer probably lies in
creating elite units. Each elite unit, since it doesn't lose loyalty,
can be the "basis" for an independent sub-faction. This would put a
premium on developing trusted lieutenants, which also seems to be a
"good thing" to me.
-- Scott T.