I think Sensei/Hachi or Sensei/Grit would probably be the best. At some point there is such an overwhelming amount of units that you can't get through. when you hit the units of the enemy you keep charging the meter and in turn let sensei/hachi spam even more units. doesn't matter if you have a colin/kanbei team for this one, even if colin is buying super units for kanbei to OHKO with I don't think it would be enough if sensei/hachi are putting out tons of artillery and infantry that completely flood the map.
Sensei/grit is another good one, sensei for early game, grit for mid and late game, switch in sensei for a double COP then back to grit. infantry and artillery are deadly, especially when there are so many infantry to meatshield the artillery.
Those are the 2 best tags I think there are, but of course in the end this all is map dependent (and whether or not black bombs are allowed)
If you can build black bombs, then the best co combination is colin/hachi. Colin gives the funds, hachi cuts the prices and spams the units. 1hp colin and hachi units are just about as good as kanbei 1hp units, so it hardly matters who the opponent is, after 2 black bombs hit a group of units they are worthless.
[23:09] <Gabo> hey guys, i have a question
[23:09] <Gabo> is it possible to transfer games from one account toanother on steam?
[23:09] <felix45> fire away lotion master
[23:10] <felix45> ROFL
[23:10] <Gabo> =_=
[23:10] <felix45> sorry I cant let that go
[23:10] <felix45> oh and I dont think so gabo
[23:10] <Gabo> the worst part is that i do like lotions <_<