the "delay/advance" pair is SSI's original naming, which we have stuck with, but in reality it is actially a Hasty attack/hasty defence mission.
A delay would be best done in the tabletop wargaming way - no terrain objetives, and points awarded for kills (to both sides), and extra points for the advancing force when it exits ground (not helos etc) elements over the delayers baseline. Naturally - that does not fit in with the code base, and would need a new game engine.
Similarily, as with tabletop games, the artificial "objective hexes" are not really needed especially in a meeting engagement. So for a human/human game you could turn them off (or make them 0 value) since a meeting engagement is really about destroying the enemy forces.
In reality (bar things like the Arnhem bridge etc), terrain is only of value if it gives you an advantage over the opposition.
(The AI - and newbie human players -
do need artificial terrain objectives to give them a "clue" about where to go on the battlefield. I would hate to think about programming an AI to "search and destroy the enemy while minimising your losses"
! )
For a human plays human (or if you are playing the AI and are player 1) then for a "realistic" delay (as opposed to a hasty attack/defence mission) then player 1 should use any or all of the following strategies during game setup -
1) Choose a bigger than average map (especially deeper, but wider also can be good)
2) And/or manually move the objective hexes towards/at the enemy baseline (perhaps at/near the exit road(s) if any?)
3) And/or make sure the advancing force does not have too much time in turns, in order to make it more "time critical" for the attacker to press on. (This will vary - e.g. if using WW2 style marching grunts, or post war APC borne mobile forces and that also affects map size (depth) chosen in stage 1, and with the openess of the terrain. Discuss with your opponent, and fine tune it over a few games by experience)
4) (possibly) at game end, add X points per surviving attacker tank, APC, truck or rifle section in the rear 5 hexes of the delayers zone and add X points per such element. (Ignore any para drops and heliborne insertions done in the final 10(say) moves of the game, this avoids gamey desants in the final minutes of the game to "win" it.)
Cheers
Andy