I overheard "mrdux" giving a seminar on crank trolling ... and one of the things he said that I've had work for me, was to always run "both ways" in an area, because sometimes they tend to hit cranks better when going in one direction than the other.

IMHO -
Pick areas that have large flats ... run those areas w/o lines out & just look for Shad schools, then troll your cranks at the depth of the bottom of those pods of Shad and back & forth thru the area of the flats that have the biggest concentration of Shad schools. This "can be done" while your lines are out, but that's where you're experiencing those "slow times". When you scout first, then fish the areas of biggest concentration, you're "slow times" won't seem so long.