The Prisoner wheels aren't a bad weight as 15" wheels go (much lighter than your high street aftermarket jobs).
185x60/13 will be fine, especially if you choose a reasonably soft tyre (e.g. Yoko A021R or A048R).
Ride height? A lot of people run 185x60/13 on stock unadjustable dampers. It depends on your local terrain. Your ride height will be reduced by 0.5" if you make this change. An alternative is to go 185x70/13, this will increase your ride height over the current by about 0.2". Yoko A021R in 185x70/13 are £34+VAT each from George Polley, superb value.
I guess you have the 15/16" wrap-around style wings at the moment? If they're bolted on then it's an easy change. If they're bonded on then not so easy. I'm not sure about the range of wingstays.
If you're only looking at 3000 mile duration then go for a softer tyre, Yoko A021R is a good all-round choice. Graham Perry had a nearly-new set of these for sale recently at a very good price.
Mike
Edited by - Mike Bees on 8 Jun 2005 10:29:30