How i made the Operation Watchman: (i'm a total nOOb and only have a Ps4)
Also-: I'm in TIER mode, but this works without the tier mode.
Before you start at 9pm gametime,
be sure you go there around 7 pm and take out the Drone jammer.
(the drone jammer will not be back on at 9pm, also
take out the Air defense if you plan to fly out)
That way you have a little bit more overview,
and can use the drone in the fight at the main building.
Be sure you call all extra support (guns for hire, and diversion)
at once the dialog with Sam fisher is done.
Call in extra Diversion again as the time is done in menu.
Keep on call in the extra support
Run out or fly out if you can
(in normal mode you will not be attacked by Unidad aircrafts as much as in this video at the end)