Some gameplay questions and a couple not

[Mobhack]

1) it is not the numbers, but the points, plus any bonus points from V-hexes. A decisive victory is at least 8-1 points difference. You were about 7-1, so just off.

"A few spotter planes" may make the difference there - if these are actually UAV with thermal (expensive) sights?. a couple of APCs - what type - if Bradleys, they may be worth an entire OPFOR mech company (thermal sights, armour, missiles = expensive).
Try a test game purchase for your OPFOR in the battl egenerator, and see what various things will cost them - if thier ecperience and morale is low, the book cost will be reduced, remember!.

2) as to advancing - I wrote an article on that, see How to attack. an "Advance" is easier - since nobody is dug in, the arty barrage is more effective.

3) Only if the OOB in question allows this - e.g. "second line" tank companies or so forth. If you really need the older kit, then you could Mobhack your own OOB, of course.