Hi,
I agree that best would be option B which you have stated, Phil. As regarding students' awareness of narcosis if used a trimix for diluent, I think that CCR diving doesn't start usually from OW (Unless now with RAID

). So I think that all divers diving CCR have good experience of narcosis effects. The point is that we don't need anything that would decrease the level of awareness while diving a machine. Any stand to change courses' standards could start from here if more instructors, IT's, and ITT's agree on this point.
So the bottom line is: Is it safer diving CCR with He on dives to 30 meters and deeper from MOD 1 ? Vote for it and make a change.
Best Regards. Wael