Paint, sand, paint, sand, lay down some trial panel lines where they won't show, paint, sand.
I think I like the old-timey pens that come in those drafting sets back in the days of Cerebrial Aided Design. Because you can adjust them, and they're way controllable, and if you build on my schedule they don't get clogged with ink after sitting in a drawer for a year.
And besides -- I'm using my Dad's old drafting set, probably from when he went to college on the GI bill right after getting out of the Navy some time between WW2 and Korea. Granted -- he hated college and he dropped out, but it's still his old drafting set, in a case that my grandfather Wescott probably made, so how can I say no?