On a related but tangential note, I heard Les Paul say that one low-tech way he and Mary got some of their neat effects when they were 'starving musicians' with little access to fancy gadgetry was to have Mary "sing into a metal wastebasket" or the like, to get "reverb." Pretty sure they also did the layering thing, recording the lead vocal and laying down a couple more tracks of exactly the same melody vocal on top of it.

And, now that you guys mention it, I do remember Les Paul and Mary Ford's recording of "Hummingbird" too.

Genie