Does size matter?

[Imp]

Firstly you are not stuck with the size throghout the campaign at the start of each battle the button for prefs is on screen & you can adjust the map size if you want to.

If you let the computer choose your vision settings & or want room to manouver tactically I would suggest a minimum map size of 80 or 100 square.

Width> base on your forces mobility if mainly on foot might wan't to shrink to speed up contact. If mainly mobile expand.
Also if use short range arty might want to expand forcing you to move it during the battle.
Height> base on number of units the more you have the bigger the map.
2 schools here really if the map is small for no of units it will be a compact battle.
If big for the number of units scouting & finding can catch you out a bit but if go to large starts to make easier as AI is spread out to so you can pick him off in pockets.
As I said adjust to try diffrences but the other important factor is time, use the clock to adjust.
You tend to get quite a lot if set lower for attacks meetings forces you to take risks.
If using a big map means you have to split forces to achieve objectives so helps the AI