Hi James,
Strangely I'd (personally) probably go the opposite route, that of oils over acrylic for the whites (as opposed to straight acrylics).
Although some years ago now, I probably had more success painting white using oils over enamel than straight acrylic. I hope you don't mind my posting these pics in your thread. Now unfortunately I don't have any pics of recent adventures in painting white, and both of these figures are early works and several years old now.
The first is a 54mm Andrea Miniatures Knight Templar, painted oil over enamel. An extremely over exposed photo, but if you squint slightly with your head to the side you can almost make out what I'm attempting to demonstrate.
This next one was a Stadden Duke of Wellington, my first "all acrylic" figure - so please excuse it's poor standard. There are many mistakes here, but hopefully it demonstrates, well, something
About 3/4 years ago I started a 54mm EVD Sertorian Legionary (the enemy of your Iberian warrior). The tunic of the fellow is also white. Bear in mind when painting whites of this period, that "white" wasn't white as we know it, but a rougher, courser white probably closer to cream. The guys over at Mike Butler's "The MedRom Forum" have very many discussions about the ancient colours and dyes - I highly recommend that site for anyone even vaguely interested in the Romanesce periods.
Unfortunately I don't have any photos of the later work on my figure, but here's one which contains some early acrylic work on the sleeve. I had started experimenting using mini painting styles on historical figures prior to leaving South Africa. Unfortunately this figure is still awaiting completion. You'll notice the off-white undercoat, to which I'd started applying a range of washes for shading. Next up would have been many thin highlight coats, followed by a glaze to tie it all together.
The thing I was happiest about with this figure was the bronze helmet. If you're interested I'll find the recipe and post it here for you.
Rudi
p.s. apologies again for highjacking your thread with my mediocre efforts
