Thanks for the Warhead Interceptor suggestion. If I spot one, I'll keep it in mind! Otherwise I'll continue to carefully transport my stockpile under a cloaker starship.
One point, though - do you still get the AIP increase if the interceptor disables the warhead? If you do, then that's not a lot better a solution than blowing up some unimportant enemy planet - I suppose 20 AIP better for not destroying the station and gate, though.