there are several combinations I haven't tried, but I'm at least convinced of this:
the bridge should be hotter than the other two pickups, whether it's 7K, 9K, or more
personally, I need tone on the bridge, too, so I bridge the mid tone pot to the bridge, but some people just wire the mid pot to the bridge by itself
FWIW, this is kinda like how the current AS strats are ... I've read the bridge is 7K (although I haven't measured mine), and the mid pot is wired "mid/ bridge master tone"