Tar paper roofing tips

When I started this blog I promised to offer some tips in addition to project updates. I haven't lived up to that promise have I. Some number of tips are sprinkled across all posts but only one post so far exclusively dedicated.
Here are some tar paper roofing tips. They come from my experience and reflect my opinion. Your mileage may vary.
1. Don't use Polyscale paint to paint paper. It has some kind of binder that makes paper stiff and hard to work with. Plus it is a waste of money. My favorite are craft paints. They cheap, dry flat, come in variety of colors and shades. Most importantly they don't stiffen the paper.
2. Prime paper before painting. I use black or gray automotive primer. Most of the time I use black. You can be a bit sloppy when painting paper if it is primed. Let black color show up a little. It adds some character. White color showing through however would be very unrealistic.
3. Most of the time I use paper that comes with a kit but occasionally I need extra. I have used black notebook paper on few buildings but then I have discovered masking painters paper sold at Home Depot in 12 wide inch rolls that I cut to 3 inch wide rolls with a saw and use in home improvement projects. It is thin and brown. When painted forms uneven surface that gives roof some extra character.
4. If roof is flat don't bother cutting tar roofing into strips. Glue entire sheet, scribe lines with a knife and paint tar lines.
5. I weather roofs with combination of oil paints and weathering powders. I use Dr.Ben's powders but any other should work as well. It is multi-step multi-day process. Sometimes skip one or another step depending on effect I am looking for. First, I place small dots of white oil paint and using flat brush dipped in turpenoid drag paint down. Special care needs to be taken to make sure streaks go straight down and don't curve. When I am happy with result I let it dry for a day. Then I repeat streaking this time using dark brown paint. After letting it to dry I apply weathering powders. I stipple, brush them on to create some random pattern. I start with white color, then use greenish black (Dr. Ben's Brunswick Green?), following with brown. After I am done with powders to mix everything I apply black oil wash. It isn't exactly black. It has some brown tint in it. I make it by mixing Ivory Black oil paint from Reeves set and turpenoid. Please note that Windsor & Newton Ivory Black isn't same color. W&N doesn't have that brown tint. However, it can be added by mixing in some brown paint. After wash dries occasionally I go over with weathering powder if I find some areas I don't like. Final step is adding rust around metal roof objects such as vents and some soot black around chimneys.
Happy roofing!