War defense as an Alliance

As an alliance, what is the best tactic to set your defense team as??

We currently set out lineups as: Any colour on the outside and middle 3 are either: yellow, purple, yellow or the other way around.

Whatever colour you decide as a tank it will drain the enemies of the strong colour.
So yellow tank drains purple opposition heroes.
As for the any colour scheme well that is random. Ideally it would be
Heal or heal debuff/ debuff and tank and hitters. (Hides behind the sofa to avoid the tirade of comments from others )

Yeah but why we chose yellow and purple was for the fact that, if you choose purple to counter yellow, purple on purple attacks is it’s weakness. Same with yellow.
But if you were to choose red, green or blue, blue on blue is just a normal attack.