Willray sez:

"(of course, half the reason I'm doing this at all, is for the
amusement
of it, so entirely reasonable suggestions along the lines of "do it
the
smart way", will end up deprecated in favor of suggestions for
byzantine
but functional :-)"

Depricate as you will . . . but the method of voltage balancing rotary phase converters as outlined
in RCM over the years is probably the best way to go. See articles in www.metalwebnews.com which
describe the voltage balance method in detail.

Bob Swinney