Erock
I make the “streaks quite random” if you do it right, you will end up with a paint job that looks like it has run off from water, or faded.
I will do almost the solid color streak in one place, then let quite a bit of the lighter color show through next to it. I would suggest trying it on scrap if your not sure what I mean.
Outline the primed scrap, then just streak in one direction (I usually hold the model, so that I can streak left to right, then back right to left, this means that the paint wont be jumping around in the bottle so much). Make sure the streaks are not dark (you use light paint flow with the airbrush). The lighter gray will get darker, and darker, and you can stop when your happy with it. Unless you get carried away with the darker color, you should have some of the lighter color showing through.
“Do I make the lines (up and down) connect to each other or space them a bit?”
I start by streaking the whole surface, or panel making sure that some of the lighter color shows through. I don’t think the spacing matters too much, just make sure that the first streaks are lightly applied. If your not sure, start with wide spacing, then fill in where you want. Then go back and streak darker in places to your taste.
I would say, just experiment on scrap, and you’ll see what I mean, pretty fast. I hope anyway.
Sorry if this sounds a little confusing, I’ll try to post some pics when I paint my Tiger I (should be next week if I can get a hold of a digital camera)