"remember that only one person has to survive the turret stages, and that's usually the tank"...
The turret fight is very very simple and here's how. Have each member shoot across the middle towards the person across from them.
For example I will use N, E, S, W
N fires S , S fires N, E to W and W to E, you get sooo much more coverage this way and everyone can see almost the entire field and react. Every 1 has 3 other people watching their back. Try it and save yourselves some headaches.