After three different attempts and three re spokes of the front wheel, I finally have the front end sorted. 500T width at 182mm finally gave me the room I need for the caliper. For those interested the spec is:
Maxton CB450 35mm forks rebound adjustable
CB500 T lower triple
Billet top triple out of the US
Morad rim (stick with Takasago, Morad quality is not great)
NHK steering damper
Custom cast iron disc rotor on the original Honda carrier
Lockheed CP2696 caliper
Honda CB750 period m/c
Avon 90/90 18 race tyre.
Plus lots of fettling, machining and spacers.