I use Dipsy's a lot also and just use the chart that came with it when bought new. Dipsy packaging has that tri-fold depth chart they include. Now when targeting a depth I use the chart and add whatever the crank dives to it.
I wouldn't consider myself very proficient at filling the cooler with cranks as we use harnesses the most. But I know the charter boats use mostly hard baits and very successful at it. So hang in there I'm sure one of the guys here will share their wisdom.