Thank you again for the pointers, you've opened my eyes! I found this all very confusing a few days ago, but having drawn these diagrams it all seems much more intuitive. Just in case someone comes across this thread in the future looking for pointers, here is an updated diagram with the tips from WeirdBits
Not sure which arrangement I will end up going for - while it would be nice to only have to flick one switch at a time, the allure of having a built in kill-switch in the pickup selector is quite strong. RE the bridge pickup shorting when reversed, the set I've ordered has an insulated wire for the negative so I should be sweet.