OK, thanks for the advice, it's as I expected - the paint has to be quite green. Masking the binding on the sides of the guitar is no trouble, but I expect masking of the thin edge on the top and bottom of the guitar is going to be a painful, or at least slow, process. Also, as my masked edge is the paint/binding join, I was plannning on not scraping or sanding the binding until after painting, so the paint may fill to the level of the binding, to some extent, assuming the binding is installed a little proud of the wood. It's going to be a learning experience, but it looks like I can recover from any early mistakes.