Need help in getting color for British truck in N. Africa 1942-43

What you be a good color mix for British 15CWT truck with the Breda gun (Italeri kit) using Tamyia paints.

I have a mixtuer of 3x White + 1x Desert Yellow + 1x Buff + 1 x Deck Tan. This was to pale (more like cement stone). I add 2.5x Yellow and it is more yellowish, but the color I see seems a bit more brown/yellow tint in it.

If you are willing to part with your family’s secert recipie, I would appreciate it.