And technically, 9 times out of 10 you'll only be able to arrange them so you get a +2 to your attack.

It is worth noting, though,that there is techincally enough modifiers to bring the damage value up to 7... which is very important if they use their Duo Attack, since the that one extra Enhancement effectively negates the Duo Attack penalty on the second attack. This allows the Duo to shoot for 6 and then 6 again (instead of 6 and 5).

It's not really that difficult since they are double-based.

Just set them like this:

_.G._._
G.B.A.G.

G = GC Detective
BA = Batman Green Arrow

Just draw line of fire with from A and it works pretty well when you're shooting from 8 - 10 range.

Yep. I was going to ask why the fourth Detective was needed, but then I realized he was necessary to get the damage value to a 6 on the second attack.
Move the detective at the left end forward one square and it's even easier.