I'm not exactly a pro at building generators, but unless there is some significant advantage I am not aware of, you general design, using many beams instead of one, would cause major lag. Each beam has to be computed individually, and that is expensive, put a dozen of the big one on a big ship in a server, and it will cause significant lag. In fact it would be "illegal" on the servers I am normally on, because this would break the "maximum beam/missile per ship" limits on those servers.
On my generators, I just glue all the supply module "bars" into a whole with one big "square" of modules on top of the "bars", reducing the whole to a single beam, minimizing the lag.