I'm just getting back into railway modelling after a lapse of many years, and am resuscitating a long dormant 00 layout, finding the same problem as Oldsalt. (I'm also starting a small business that will eventually produce structures for the larger scales, but that's another story.)
The only source of 00 standards I have is "Starting in Scale 00", published by Peco in 1961 (which I bought new for 2/6d!), and the dimensions given there correspond precisely to Jeff's. Does anyone know of anything authoritative that is more recent than that? There must be something. The MOROP norms (http://www.morop.org/en/idf/index.html) are useful, but seem to ignore 4mm scale, though they can be scaled up from H0 easily enough.
(Incidentally, I have discovered an excellent way to weather your nickel silver track. You simply store it for 40 years, allowing it to develop a heavy tarnish, then clean the running surface with a rail cleaner, and you have rather good looking track.)