Resa,
Daft as it sounds I just used off the shelf red oxide primer in a rattle can the make I used will not be available in the US but you want one that is a little more red than brown looking, XF64 Red Brown this is a very good shade and XF58 Olive Green as you say XF61 Dark Green is several shades to dark, to thin the paint I used Tamiya thinners filled the jar I have just emptied by about half (50%) gave the jar a good shake to clean out the jar added that to the paint then shook again, for shading I painted the base colour then added 100% of either black or white to the remaining paint and 100% thinners this was then painted on to the tank black mix for raised areas, tools, welds and folds white mix was used in the centre of panels then using the base colour again with 100% thinners you paint over your shading allowing the shading to bleed through to the desired amount
I then added the camouflage and repeated the process adding black/white to the green and brown and again with green/brown plus 100% thinners paint over the shading again to the desired effect
