Hi Justin
I wondered how long before this arose
Google and few other browsers are now flagging if not accessing by https
Your correct in SNI ssl alphabetical list, my solution was to setup 1sh as a domain.
Your idea is sound, but please remember websites I believe are now been scored lower on google if no https is available
It might be more prudent to advise clients to upgrade to LE ssl and job done, thereby giving them the extra benefit of higher google ranking
I hope that helps a little
Many thanks
John