On those grounds, combat patrol and Crusade sounds best. That way you have incentive to build up larger forces, but the actual games themselves can happily stay small scale - you just have a greater choice of units to bring to them.
This also stops the games becoming a case of "oh hey look, it's my original
HQ, 2 Troops and extras against
your original
HQ, 2 Troops and extras.
*Again*."