Brainey - if you haven’t already, you may want to post this on Cruisersforum.com
We sold a composting head there last year. Had several people wanting it. Sailboaters & RV people seem to be more interested in composting heads than powerboaters, for whatever reason. We have all three, tried the composting and I (the wife) didn’t warm up to it all, so we sold it.
You should no trouble selling it!