The Camano had an option of a manual Jabsco head or a vacuflush from the factory. Obviously, a pre owned Camano could have any head that was ever made.
The fact that it has a Jabsco head does not mean that the holding tank is a Jabsco. Mine is more or less square but with a "V" shaped bottom to take advantage of the "V" shaped hull at this point. I've never looked for a manufacturer's name
It is listed as a 14 gallon capacity and is translucent so you can see the level of the contents (unless it's totally full or empty). A flashlight helps.
I installed some sort of gauge that uses external sensors. It measures two tanks so I installed it to measure one of the potable water tanks and the holding tank. It works fine on the potable water tank but the holding tank side reads full all the time unless I manually clean the "poop" off the inside wall of the holding tank. If I do that, it will work for a while until the poop builds up on the wall again.
BTW: That tank is 14 gallons because that's the largest tank that would fit in that space. Bigger would be better but there's no practical way to do it. Possible perhaps but not practical. And marinas charge the same for 14 gallons as they do for 100 gallons.