Phil, you have 4 sets of actuators?!?! Damn!!!
Tzucc, they have a new system, the Odyssee V, that requires no platform. Instead, it is built into a set of theater seats that have been reinforced to handle the motion. I don't think the Odyssee V goes beyond two seats, though, so it would be cheaper to use the platform.
I have a 10' wide platform on an XL set of actuators and it is really a lot of movement.
Another option is to flush mount the platform with the floor. That is hard to do, as you need to recess the platform 6" into the floor, which not many people can do. So, your best bet would be with a platform in the back row or with the Odyssee V in the front row.