There is a note (somewhere related to those songs) that says it was sometimes done with the feet - nearly all the pictures you see are of it being done on a table with the hands. One of the songs is slower than the usual pace - maybe that explains why.

The old lady I was talking to spontaneously started moving her hands in a waulking rhythm when I tried playing her one of the tunes (before I found the sound files; using the notation in "Tocher", which isn't very good).

Economics of the enterprise: it kinda makes sense that quarrymen's wives and daughters would do waulking, taking the fabric in to process. Despite having babies in bulk (13 children for one local family of that generation) they would have had more free time than the wives of agricultural workers, who had to tend animals as well.

There is an attempt to revive weaving in the local area, as a rather upmarket business: http://www.ardalanish.com/