That's a nice looking depth gauge. I've got the Ryobi battery powered tools and was thinking about buying the chain saw for just that purpose. I assume that the depth gauge can be easily removed and you've got your original function back. I have seen a C-clamp used, but I never felt very comfortable with the way it looked. Now if you'd only design a dust collection system for it that hooked up to a shop vac.
My one experience with routing conduit inside the ICF form was not good. It has to be water-tight, otherwise when using a high slump some of the fines can leak into the conduit. The only way to avoid that would mean gluing every connection. It doesn't take very much concrete to solidify and make pulling wires impossible. The loss of time and materials makes me sceptical of using such an internal conduit system unless it was really, really, really necessary.
Mark Fleming