I believe it has more to do with the machine using the power than the transformer. The machine requests the power, the transformer sends it. It is not constantly sending packets. Therefor, depending on what machines you have running, each line could have anywhere from 1 to 4 packets of 128eu going into them each tick. So, for example, a single MV transformer on an MFSU fed line should be able to feed all four faces of an Industrial Grinder, no matter how you have the wiring set up. Note that I have not directly tested this myself, it's only what I've picked up from a lot of messing around with IC2.