I confirm the secondary tables overrides all
I tested those values: (invisibility up to 1 meter, visibility of non-hidden at 2500 meters, and hiding in scrub/forests = detected at 10 meters distance)
And I could do this in a battle
Hiding javelinmen until discharging at very close range:
Hiding a bunch of big melees 100 meters at the right of my right flank until coming out:
Was incredibly fun, but as Krixux found out, the AI can only cope with what it sees, so I completely destroyed him with those "realistically OP" hiding values.
It is clear that the AI has a tendency to form correct strategies when it sees all your units. Like some reported, the units I left unhidden were very correctly managed and attacked/flanked.
So yeah, if you want to edit hiding just edit that table. I left land_units completely untouched and it worked as is.
Side note: in a multiplayer campaign head-to-head "play as AI" only game, a submod where hiding is represented nicely and realistically set it would be super ingly awesome and forests/scrubs would really mean danger and traps.
Double on the side bonus note:the AI was also hiding its units in a smart way and in the late game it ambushed my general unit (didnt see it coming thanks to 10 meters hiding) from the far left forest as I was mopping the rest up. I destroyed it but the move was genuinely awesome and the unit clearly used an ambush path, not just "parallel direct approach" classic.
AI hiding potential could be a double edge trick to metabattles.