The Lehigh cheek slap comes from a couple of different things, but mostly it's from how your cheek interfaces with the comb as you are lining up the sights. Most of them don't have enough drop there (forcing the shooter to engage the stock with their head crooked over at an angle), and/or the "corner" as it moves to the top of the comb is too sharp. Putting in some cast-off can help with both, as can deepening the "concavity" in the cheek piece, and making the cheek rest protrusion very small.
Most shooters need between 1 3/4"-2 1/8" of drop from the sight line to where their cheek engages stock. Build in less than what you need and you have to angle your head to get sight alignment, (and Lehighs have notoriously low sights) and the corner of your cheek bone is right on the corner of the comb rollover. Whammo---cheek slap.
So since the comb angles upwards (unlike an M-16 that is dead flat parallel to the bore) the drop of the stock at the heel isn't that important. That's for your shoulder. What IS important is how you shoulder the gun, and where your cheek engages the stock forward of the butt. That will determine where your drop at the comb will be at the ideal height to acquire a proper sight picture, with proper head alignment.