Ah. How tedious. Well, knuckle down and do the typing then. It won't take as long as you think.
Skill: yes, that's exactly it. You can set a loon's skill in the skill bar when you place him in the Editor. You can change it during the mission with the setSkill command. I wouldn't recommend that for normal gameplay, but it's fine in a cutscene. The difference between min and max skill is significant.
Unit choice. For example, snipers and machine gunners are the best units for long distance stuff, so give lots of them to the side that you want to win at long distance and only a few to the others. LAW soldiers have a lower camouflage rating (I believe) because they have a dirty great launcher over their shoulder. Mortars and Heavy Grenadiers can be devastating to infantry in the open, if you can persuade them to fire. If you are not familar with the vices and virutues of different types its worth spending an afternoon inventing wee test missions and just playing around with them.
Unit placement. One well placed unit can take out a whole squad. If I want to put a sniper at the bottom of a tree I'll Preview the mission either as the sniper himself or a temporary observer placed next to him. It takes 5 - 10 Previews to get him in the right place once you have decided which tree, and that can take 5 - 10 attempts in itself. Then you playtest it to discover if you've got it right. It can take a whole editing session to get one sniper in just the right place, but once he is there boy is it worth it.
OFP is a very sophisticated game. Part of the skill of the mission designer is learning how to make the best of what it can do. Scripting (more than one line of code) is a last resort.
Edit: this was written before HateR_Kint's reply. I confess I thought it would work. Max knowsAbout value is actually 4, and yes, the unit won't necessarily attack at once. If the unit is too far away to have a high knowsabout value he's probably too far away to attack anyway.