Just to clarify the generator thing. I mean turning on the generator on the first engine after 12% has been reached on the second (start in progress) engine which it sounds like you are doing anyway. Like you said this reduces stress on the generator.
If you did turn on the generator on the second engine during start it should have no effect. The starter takes priority over the generator, ie the generator would drop off line not the starter. I do seem to remember this may vary if you have older generator control units, so don't quote me on that one.
Cheers
Ian