Hey there KB250r! Pretty sure I remember you from 3WW. Glad you could make it. This site is second to none when it comes to the 250r's.
I kind of wanted the quasi-stock look as well and I can relate.
What I did was painted my ESR 350 cylinder black and left my crankcases black. Now, I realize the head and shape of the cylinder is a dead give away to those who are familiar with the 250r. But let's face it, most of your modern 450 riders wouldn't know a 250r Big Bore if it fell out of the sky, landed on their head and started to wiggle!
I understand my reply doesn't really pertain to your initial question, but I thought I might offer you a different angle on it.
Here's a couple of pics of my set up. I thought it came out well for just me and some good brush on paint...