"the ungrateful idiots" probhably leave the stuff on all the time, and balancing it would be as easy as moving some two wire circuits from A and C to B, if possible. (If this were a wye system, it would be very easy)
Now more questions: What happens to the neutral in the transfer switch? Where does the neutral come from on the gennie? (Corner/center tapped delta?)
"put it under load the needle starts bouncing all over the place, the flourescent lights start flickering, ups systems start getting unstable, and it fries boards in the large 3 phase sorter." - Sounds like neutral drops out, and phase reconnect to me.
