I am one who really does not like new words tacked on to old tunes. I think they deserve a tune of their own and the regular tune and words need to stay linked together. I also do not like parodies..not for that particular reason...the mean reason is I think it takes something lovely and makes it into a joke, like drawing mustaches on nice pictures. But I don't mind hearing a joke once. I would either attempt a new tune, or collaborate with someone who produces tunes easily, or turn it over to someone who can fit the tune to the words. Of course, sometimes it just jumps on to a tune and then nothing can be done except to use it. But I wouldn't try it out on various tunes and say, "oh it works to that one.." Mathematically, it probably will about 13% or so of the time, but so????