Ok, a while ago i was colouring a tank from a friend. This was an 3 Camo.
So what i would do:
1. Filtering
yellowbrown - ockre all around, suspension grey-braun to get to colors more homogenious
2. Washing with black
to get more dimensional (doors )
3. mate varnish
4. Tamiya XF 51 Khakidrab ( Shadows )
around corners, bolts, suspension

5. Chippings with grey ( Tamiya XF 24 or Germangrey ), Umbra( very dark braun, close black, little, older rosty chippings ), desertyellow ( the colour what you use for this, made this into the green and braun ) Sponge Technic
- Suspension
- Fenders
- around the doors,handles
grey is very good for german vehicles cause the most ones where grey befor they became an camo. Also fit very good to all your colours

5. Scratches
Here you can use XF24 or Germangrey ( scratches not going down to metall )or/and Umbra( very dark braun, close black, little, older rosty scratches), and / or desertyellow, brush 10/0
6. Rost
real Rost Set, or different Technic, not to much just special parts ( regular metall, no Tanksteel)
at Muffler, some Screws/Bolts, Handles
7. Smoke Tamiya XF1
spray this cloudly with airgun
Barrel, MG, Airintakes ( very thin )
8. Dirt
For Dirt you can use From light grey to brown. In your Fall i would say something like light grey

9. mate Varnish
10. last but not least Metall Effects with Graphitpowder
Hope this will help you a little