Not least of the reasons I like it is that you don't really need to "sing" it. I think Rice just sort of "talks" it, sometimes almost whispering it.
I have lots of trouble singing in public, too. This is one that I am comfortable with. Very simple lyrics, even. Or make some up. Check what Rick Estrin has done with the same concept. He has his own words and applies his more "lyrical" singing style, but you get the idea.
You already "own" the tune, Surveyor, why not let the ol' horse outa the barn and give a try singin' it? It will set you free, musically.
surveyor- do give a spoken word style of vocals a shot, you don't really even need voice lessons for that. let alone the great job on harp, my compliments! sbwII was noted for the laid back approach to both playing and singing, there's no reason you couldn't work in that vein. just one man's opinion.
both you and mr. estrin have really dug into how sonny did his harp work and gotten great results. it's an area i have yet to get far into and you both have my respect. carry on!!