So, I feel like I'm having a bit more success with smooth blends, and I'm at least seeing some results. I'm using a two-brush blending technique - essentially I hold a damp clean brush in my mouth, use the colour brush to apply some paint, then quickly feather it with the clean brush. Rinse, repeat.
While experimenting with this technique (which I'm preferring over wet-blending at the moment at it seems more suited to the tiny areas I'm working on), I'm refining as a I go.
I've found that increasing my thinner amount to the point that the paint is basically like skim milk is helping immensely with the blend, almost to the point of not even needing to feather with the second brush. I load up the brush with paint, draw the stroke from where I want the least amount of colour to where I want the most, and lift off. Where I start the stroke gets so little colour it's invisible, and where I end the stroke gets a pure new colour, with a smooth transition in between.
It's not perfect, and there's areas I want to go back over with the base coat, but I'm finding it terribly effective - you can mainly see it on the chest plate.
Anyway, I've applied the last two highlight layers for now, let me know what you think.
3) 2nd Highlight: 1SG:1MB:1EG:1EB:2T
4) 3rd Highlight: 2EG:2EB:3T
Next up is to clean up the transitions by reapplying the base colour, then the three layers of shading and defining the lines between the armour segments. Then another highlight, wash/glazes if necessary, and finally edge highlighting and hot-spots. Phew!
All paint is VGA. Colour codes are:
Dark Green = DG
Magic Blue = MB
T = Vallejo Airbrush Thinner
Sick Green = SG
Escorpena Green = EG
Electric Blue = EB