To set the cutting iron depth when sharpening a spokeshave, use the two adjusters one at a time to lower or retract the blade until it looks parallel to the sole of the spokeshave when looking along the sole of the spokeshave from the front edge. The more blade is visible, the deeper the cut will be.
How to Sharpen a Spokeshave - Honing a Dull Blade
Sharpening a Plough Plane, Common Woodworking
How to Sharpen a Spokeshave - FineWoodworking
Woodwork Forums
Veritas MK II Honing Guide
Veritas Small Blade Holder – Olly Writes
Boggs Side Chair Build #20: Hand Shaping, Part 1: Tools — Jeff Lefkowitz Chairmaker
Stanley & Record 151 SpokeShave Sharpening Jig
Spokeshaves 101: Sharpening and Usage - The Renaissance Woodworker