A belated thank you to James and Ed...
James, the paint work was quite the trial and took me over 6 months to complete.
Surprisingly, no one has asked how I did it without masking at all.
Fifteen coats of white paint went on the model before I started painting the black pattern free hand. If I needed to straighten up a line edge, I scraped it away with a sharp exacto blade and basically carved all the detail into the paint job where needed to make the edges as crisp as possible. Overall, it was still all free hand and by eye.
Thanks again,
John