In this SBS I've used colours I wanted on my model, so they are not a de facto standard to get good results.
It's important to start with the lightest colour and work your way towards the darkest one. Patience is the key here in means of drying time, but a hair dryer(not the wifes), will speed up the drying process.
First I mixed a light mix of MIG P026 Concrete, P028 Europe Dust og P037 Gulf War Sand. Put it on with an old brush and used Pigment Fixer to set it.
On top of the front fenders I sprinkled a dry mix of pigments in the same colour blend, dipped a large brush
in pigment fixer and just touched the edge of the fenders, and the capillary effect did the rest of the job.
In this step it's important not to touch the pigments with the wet brush, let the fixer flow freely and allow it to "surround" the sprinkled on pigments.
This is to avoid the "flattened" look and get some structure in the mud.