Thank you John, Pedro A., Pedro S., Les, Keith, Ron, Orlando, SG and Colin. And thanks for the likes as well. Glad you like him.
Sorry for my late response, I've been travelling over the past 2 weeks.
@SG: Thanks for the added info.
@Les: I used the following mixes (all Vallejo acrylics)
Base: 940 + 987 (5:2 ratio)(with Tamiya X22 matte medium mixed in)
Hl1: Base + 987
Hl2: Hl1 + 986 (both highlight colours give a faded looking base colour)
Sh1: Base + 822
Sh2: Sh1 + 950
Next step was the medium green areas with 940 + 847 (4:1 ratio)
Then the bright green spots: 857 + 847 + Tamiya X22.
On the helmet cover I used 833 + 953, with a touch of 940 and 913 for this to get some colour variety.
The darkest spots I did with 822 + 896.
I made the mixes in an empty press-through chewing gum package. After a session I covered it with broad tape and kept it in the freezer. This way you can use your mixes for a few days and you don't have to mix everything for each session.
To give the spots a nice sharp and rounded shape I used an old 5/0 acrylic brush with 'hooked point'. Normally such a brush is only good for mixing paint, but I accidentally found out that they are good for getting the spots just right. If you thin the paint quite a bit (1:1?), the hooked point can be used to apply a 'droplet' of just the right size. When the drop evaporates a nice sharp-edged spot of the right size and 'roundness' is left. To get good coverage sometimes a second layer is needed (after letting the first dry).
I hope this is of use. I wish you much patience with your version...!
Cheers,
Adrian