Go softer with the bindings, like F2 Carve RS or Burton Race Plates/Ibex. Set your hard boots as soft as possible. Even walk mode on the rear...
158 sounds like good size. However, the length is not as crucial as the flex and the width appropriate for your boot size and the angles you want to run.
Set the rear boot to slight overhang, then front to the desired splay. With very low angles, you need less toe/heel lift than on race board, but you might want some inward canting on the rear. If duck, you can go flat, or just inward canting on both.