I wonder how would sawdust work in composting toilets?
Is there a preferred ratio of poop to coconut fiber or peat moss?
Which one of the composting toilets is the smallest (best able to fit in a small boat)?
I don't know that there's any ratio quoted; you charge your unit with the amount specified by the instructions, then add more if it doesn't seem to be doing the job. My C-Head takes 1 1/2 to 2 one-quart jars of peat moss; the others are larger and take more.
Of the three we've been talking about here (Air Head, Nature's Head and C-Head), the C-Head is definitely the smallest and lightest. That doesn't mean it's flimsy, though; it's solid as a rock.
There are basically three models, if I remember right. The original, which I have, is great for setting against a vertical bulkhead. There's another one with a smaller footprint in the back, for fitting into corners better. And the third one has the bottom clipped at an angle in the back, so it'll fit better against the sloped side of a boat.
I'd post links or pictures, but I haven't reached the magic number of ten posts yet....