Darksiding an XJ900F

I recently acquired an XJ900 pre-Diversion, which comes with quite skinny 18" tyres front and rear. Since my ultimate aim is to Darkside it and go touring, I started by looking at the options and possibilities. First up, the front tyre was worn and needed replaced. Happily, the 18" front size is available as a rear size too, and a Maxxis C907 rear of 100/90-18 went on there just a few days ago, after I'd had a careful look at the profile of it.
First day  was warm and dry and a perfect day to scrub it in gently, just in case of any unexpected happenings, although I didn't seriously expect any drama. It turned out well, and after a few tens of miles on the twisties around here I started to open it up a bit, gradually exploring and extending the bend-swinging capabilities of the new front.
It was absolutely fine - not a single moment of uneasiness, or squirming or uncertainty of any kind.

Yesterday I took it out in the wet - now, normally I don't like wet riding much, and avoid it as much as possible. I've done too much of it in the past when I had to, and don't enjoy it any more, but I used the weather to find out more about the tyre.
It was absolutely fine in the wet, too.

So, there you go - the first step in darksiding a skinny-tyred bike of 80s design, albeit ass for elbow.
I'm now looking at what 15" or 16" wheels will fit the rear and run a Nankang 135r15 (which are easily available here and I have two of already, sitting waiting to go on) or a 5.00R16 (more difficult to get, but show up from time to time).  
If I can be bothered doing a rear drum conversion, a Maxim wheel will go in, I'm sure, but my current favourite is the V-Max early years, as they came with disc on a 15" cast rim. I would probably have to re-jig the brake torque arm, but since I'll only be fitting a relatively narrow CT, I might find there's sufficient clearance as standard. Probably have to change axle spindle and caliper carrier, too, but that's no big deal.