They appear to have a great shape to them but being leather instead of canvas you'll always have that going against you. You could paint the details on (but it'd still be leather) OR you could glue the strips of fabric over it.
I suggest plain simple grey... the one that's available near you. then wash and some spray some correct colours of weathering, that should help in getting the right colours. The CA boots aren't the right colours either, but they have a nice base, plain black and grey, and with some washes and sprays... there ya have it.