Narrow diamond won't usually work.

The key to counter formations with 3 players on each side is to use formations with 2 players on each side and attack at least partly the middle.

this can be a defensive formation with dl/r and ml/r which counters through the middle, or an offensive formation with dl/r and aml/r which attacks mixed. In the second case this means that you should probably have also an amc, and probably press high.

I favor the first solution. 4-4-1-1, 4-3w-1-2 or 4-1-4-1 depending on opponent's strength would be my choice in this case.