For our in-line boards: We use Trilene XT 10 lb in the dark green color. Also we have been trying out Blood Run Tackle's Walleye Mono. It is 16# but has the same diameter as 10 lb Trilene. It seems to be bit tougher than the Trilene and where you clip your boards on the line it doesn't get nicked up as much.

All of the dive curves for pulling crank baits, in line weights with harness's are based on 10# line. It's the drag of the line in the water