I don't instruct yet but I just put a 'full helmet' setup in my Bell M4. Since most of my friends who instruct use the Chatterbox setup and I still have them ride with me I wanted a full time system they could easily hook into. The trick is to get the speakers where your ears are.
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I basically deconstructed the lower padding section and inserted my ear speakers and mic bud just under the liner, then hot glued everything back together. FWIW, this was All hot glued from the factory.