So, I managed to finish my test marine today:
Knarloc Green and Boltgun metal are the two main colours, with Dheneb Stone as the base of the cream accents. I'm fairly happy with how he turned out, although I could always be a better painter - my edge highlights are somewhat iffy in some places, and in hindsight Fenris Grey may have been too 'blue' a paint to use to highlight the black, but I guess you live and learn... He's not had any decals applied yet, as I'll probably wait until I have a squad's worth and do them all in one fell swoop!
With this lone finished miniature, this brings the tally a step back in the right direction, to:
1 vs 5 = -4
In all honesty though, I think the thing that I'm most surprised by is the lack of 'you can't call them nerdmarines that's not canon' comments on my previous post, maybe I pitched my tent in a more civilized corner of the internet after all...