Here is how you make castable mini planer boards you can steer.
They plane to the left or right and flip direction with a flick of the wrist.

Print this pattern to scale, paste it on a 1/4" thick balsa wood or pine board and cut both pieces at the same time.
Drill the hole to press fit a piece of WD40 tube and paint thick for more strength and casting distance.
Use a toothpick to set depth or slip rig.

You can scale it up or down adjusting wood thickness to suit.
For my Stealthy Trolling Methods read http://www.bulletbobber.com/fitrforparoo.html

Pattern Compliments of BulletBobber Enterprises