Thank you for the link it was very interesting.
On the rear tyre, why not move it up higher so that it is centred on the sandshields and then lash/tie it down with several loops of rope. It need to be fixed in such a way that it does not swing around.
On the colour scheme, I have have noticed several discussions going on this site and other sites. What I notice is that each patrol in the LRDG had its on particular scheme for themselves. As a result the variety of schemes would appear to be considerable. Some would have bee sprayed some hand brushed. It really depends on what scheme you pick. Have a look at some of the LRDG sites this one gives you a basic understanding http://www.lrdg.de/vehicles2.htm
I hope this helps
All the best