This is what I do:
Full backs - Mark front/back post
Tallest centre back - Mark tallest player
Other centre back - Man mark
Central midfielder with best marking attribute - Mark small player
Other central midfielder - Man mark
Right winger - Edge of area
Left winger - Go back
Forward with best heading attribute - Go back
Other forward - Stay forward
We don't concede many and are a threat on the counter-attack.
I might try that, but I play more of a 4-1-1-3-1. Does that mean I should choose the AMC to go back like you do with your forward w/ best heading attribute or just choose one out of the attacking players w/ best heading attribute? Just wondering what's your opinion for different formations.