Yes, there is a chart. Whether it is behind a planer board or not, it will still dive the same depth. I don't think at 1mph you'll get the action that you want with a 300. If you try running faster than that with an inline, you may have problems with the line coming out of the release. I haven't run them that much, so someone else with more experience could probably give more advice.
Here's the link to the charts.
http://www.crappie.com/crappie/showt...00-depth-chart