Hi EJ,
I've been preshading for two years now so I'm still fairly rookie at this, but I've found that you don't actually have to have nice, straight lines. Just preshade the lines roughly. The idea of preshading is to highlight the panel lines, then "fill in" the top coat in between the lines first before a final, complete brush-over. So we're talking about thicker coats on the unshaded areas and lighter coats over the shaded lines to bring out the detail. I'm not sure if I've articulated it right, but you're basically "erasing" your crooked lines when you paint over them. Also, I use li