The lozenge shape emerged with the BTR axle, and there's a difference of up to five inches, front to back. It can catch people out with narrow drives. It nearly caught me out in 2008 because I only measured the front track.
In 2004 the 4/4 had a narrower crosshead. Plus4 and Roadster the same width until 2010, when the Roadster went wider when the Roadster Sport was introduced.
The tyre issue is complex because 4/4 wheels have a greater inset than either Plus 4 or Roadster. It's in my book and also on the MWS website. Only a few mm, but do not assume all 185/70s fit because they don't. The pinch point is the upper spring mounting on the end of the crosshead. In 2016 I asked the factory if they would fit Blockleys from new. They agreed but found that they didn't clear the spring mount, whereas the Avons do.
195s will not work on 4/4 wheels. MWS said that they can squeeze a couple of mm by tweaking the spoke settings, and the offset/inset figs reflect that, having a plus/minus a few mm in the dimensions.
SO.....always check the front clearance on 4/4 wire wheels, even on 185/70s.
