We spray the bowl with a water/vinegar solution after every use.
In mild weather where I’m wearing full foulies and many layers under it can be a lot faster to stand than sit. If the boat is heeling heavily or bouncing around I always sit.
The OGO looks interesting and pretty well thought out.
One nice feature of the NH is that you can pee anywhere with the poop flap closed. There are drains that prevent pee from going into the solids tank and allow for standing use even on a healed boat.
I buy coir in this big and dense block (many kg) that you break up with a pick and hammer. It’s about $20 for a multi year supply at a good hardware store.
This smaller pack would probably work well with one slice per use:
Coco Bliss Premium Coco Coir Brick 250g, OMRI Listed for Organic Use...
Don’t underestimate how quickly you’ll fill the pee tank. We empty the 2.5 gallon one daily when cruising (2 adults, 2 kids) and twice daily when doing long sailboat races with 8 crew. The tiny c-head pee tank always scared me away. I’ve often thought of making an external pee tank for our NH...