I have made a 1/4 size batch of this and can add the following:
1) Based on similar recipes I found online, it is 2 Tablespoons of both white mustard seed and celery seed (I couldn't find white mustard seeds, so I went with yellow.)
2) My 1/4 size batch made five full pints. I can't really imagine trying to do a full batch - you would need HUGE pots.

Pete