Slant 6 Megasquirt Ignition (Crank&CAM position sensing)

What are people using for crank and cam position sensing with Megasquirt on their /6? I was hoping to avoid a crank-shaft position sensor in favor of adapting a "high resolution" cam shaft position sensor (replacing the distributor, obviously). But, from the documentation, the only option I find for a high-resolution Cam Shaft Position Senor is a Nissan optical sensor that is not supported by MS2 (Microsquirt):-( So I'm curious what other people are using.

BTW, my only concern with the crank-shaft position sensor is that it seems rather exposed! I'd hate to have some road debris or something take-out my trigger wheel.