I think I used farm output last time, for 99% of it. 1% was from a connected "dump stuff you don't want into here" chest.
How does your MFSU factor in there?
I may just end up using MFSUs in parallel to feed my base. Its easier in series to gauge how much you have, but in parallel you can send out more amperage.
I wonder if there's a way to "add" redstone signals. If I have, say, 4 MFSUs, each with an energy detector, I can turn on my generators when the total redstone signal is too low. Alternatively I could just turn them on when "any" signal is too low, that would work too.
I guess I have a solution, I just wish it were a GT one.
The MFSU factors in in two ways: First, it stores the IC2 power coming out of the reactor before I transform it to GT power, and second it contributes 40 million EU to the total power storage of 140 million dedicated to the reactor's output. I guess I could dispense with it, make a bigger GT battery buffer and another energy orb and transform all power directly into GT power as it comes out of the reactor, but I didn't want or need a 2 amp IV output because this would affect my backbone power wiring throughout my base (not that there is much of that yet), doubling its expense in platinum.
As for handling the redstone, perhaps a look at Automagy's redcrystal will help. I recall it has a way of capping redstone signals, so that you can make a crystal emit a redstone signal if an incoming signal has a minimum or maximum strength. I was planning to use that to control PneumaticCraft pressure but didn't get around to it yet. If you use that and use a few AND gates from BluePower, you might be able to make your generators switch on if X or more of your power storage devices go below a defined threshold.
I would prefer a GT solution as well, but GT isn't good at redstone logic, while Bluepower - the next-best tech solution - isn't good at analog redstone. We'd need Reika's redstone mod (forgot the name) for that, which I sort of miss I should admit.