For a Valor with 1 FG, 3 Flaks, 3 Cerbs, 1 Missile, All secondaries and 1/2 Pulse(s). That's 9 groups you could ave and you would get around to using all groups in a single fight on a heavy Battleship like the Valor or something like the Hessian BS. Minus the FG and you have 8 groups and then you could easily have a group for Flaks if your "Fire Missile" button isn't mapped which brings it back up to 9. You could even have one for CMs for when you're in cruise.
And then if you don't have Cerbs you can put Razors, Missiles and Mortars on which would need even more groups. Also you could have another group to chainfire weapons.
I would love to see more weapon groups implemented. 8 would be perfect.