Yes on the filenaming convention; Mmario & Mary are naming them the same. Mmario has one with a variation that he has named with this convention: ss--b, where the dashes are the song number.
Tempo-- err on the side of slow.
I've been out all evening and got to hear two of Mmario's real quick, before I left. It sounds obvious to me, tunewise, how a call/response pattern must be involved, although the transcription does not specify this. Melodically, one person just would not sing the two phrases involved putting them together as one song, although it is possible one person did sing it as one song for the purposes of transmitting it to a transcribing collector. (I have presented them the same way myself in fact, when trying to teach them to new audiences; I have to sing my part and theirs, too, until they see the pattern and take their part off my hands.) So on the one I heard in particular, it MUST be a leader/group call/response thing.
I'm going to be looking/listening to them one by one as they come in and see if other things emerge from being able to look and hear at the same time. But I can say this already-- as one who has performed many of this genre in recent years, as well as blues gospel-- it makes a huge difference already getting to hear the tune echoing in my head without making any effort at all as a musician to produce it. It sneaks in and makes itself at home and starts me off improvising, just as the genre is meant to do.
THESE WERE MEANT TO BE TRANSMITTED BY HEARING, not reading!!!!!
This is SO COOL I hope we will be able to get enough people involved to do them ALL.