I looked at what I though was every option under the sun and found I had 3 basic choices: Millaz (champagne glass), Dragway (Cobras) or a selection from other manufactures (inc Simmons etc) that looked great but were not what I was after. I checked the offsets on American Racing, Vintage and Trigo and found that the only option was to extend the front guard which I wasn't too keen on.
Check out my gallery and you will see the wheels attached to a car that is sitting on the hoist in Warwick's workshop. There are also some photos of the same size wheels (with tyres - 255/50x16, 225/50x16) on another Harrison's. On the rear, you can see what I mean about the extra 10-15mm offset that may be able to be achieved.
(NOTE: these photos may be confusing
since the wheels look the same and the car is the same colour but there are two cars here and two different sets of wheels!!)
I will post some measurements in a couple of months when the wheels and rubber come together.