[fresnojohns]

Quickchange,

Darla answered your question perfect. I really don't have to add anything.
When you talk about over an edge, like the space between a set of doors,
as long as they are totally lined up with each other and not higher than the other one may not have to touch up some time as the heel of the brush will
keep the paint flowing right to the tip of the brush. Another thing to think about is the brand of brush you are using. Mack brushes for me are great for
designs. Some people use them for line work. For my long lines I use
Scharff 2190. They are about 12 dollars each. I like the longer handles too. Handles are about 4 inches long.

As for doing line work, its great to do it 100% no guides but you can't do that all the time. Say you are in the middle of ??????? a corvette door.
Use quarter or one eighth tape as a guide for your finger to pull a line.
Hope this helps. Its only a guide don't touch tape with the brush.
Hope it helps talk soon.
Fresnojohns