Sounds like a silly question,but am going to start the camo on my Tiger II .so should i apply red brown first then the green.i now dark colours go on last but to me they both seem dark coloured.am using Tamiyas XF 64 red brown and XF5 green.not all colours will meet but there is some places that they do.cheers

One trick I use when unable to decide which colour to use first is to look at them and screw up my eyes. This exagerates the tonal values of the colours allowing me to see which one is darker, this will be applied last where possible.
If this doesn't help I then I paint some scrap plastic as a test, trying one overlapping the other and vice versa to see which works best.