Hi,
Barbara K, Thanks for the tip on Blue Hole divers and FantaSea, that sounds like Plan A.
ScubaSnack, your method sounds pretty similar to what I'm thinking of as Plan B. I have an old pair of little round "John Lennon" glasses that I can take the side arms off of and replace with some sewing shop elastic to hold them on my head independent of the mask. I don't know if you get the Canadian made "Red Green Show" down in the USA (maybe on your PBS network somewhere), but for Red Green fans up here, anything you can do with duct tape counts for bonus points. 8-)
Thank you very much to everyone who replied.
Three weeks from now and I'll be down there.
cheers -- bintipa