This has been a really interesting thread for me. The only thing I might offer to the discussion is that once you've conquered the mask clearing, it may help to keep practising the skill, so familiarity and confidence with the technique is not lost over time, but is maintained and hopefully grows.
I personally don't find mask clearing per se a problem, but taking the mask off entirely is a bit more tricky.
Like many people I don't like opening my eyes underwater, and I find I have to concentrate to ensure I breathe with my mouth only, maintaining slight positive pressure to prevent water getting in my nose.
However, I've practised in the pool so I can deal with this situation if it should arise, and this builds confidence. I also practice taking my mask off completely, and refitting it and then clearing it, whilst diving in the real world. The more often you do it, the more in control you will be as your confidence grows. Yes, it's difficlut to force yourself to do this exercise the first time, but it does get easier.
Last week I was on holiday in the Red Sea, and practised several times at depth, concentrating on breathing steadily and evenly while I performed the exercise, so I didn't breathe too deeply and start rising towards the surface. If it helps, you could get your buddy to place a gently restraining hand around your stab jacker waistbelt, just to steady you and stop you floating off as you conduct the exercise.
I'm going to try some of the techniques discussed in this thread. One thing is still tricky though - I dive in UK waters, and the shock of the cold water on your face when your mask is removed does make things more difficult. But I'll keep practising, so I know what to expect, and so I can deal with it in the future.
mike