I've done many of the low buck dumpster diving projects...
Another problem with the Cal 9.2 is that the holding tank
was a VETUS bladder under the V berth. This issues, smell, odor, stench, and low volume..
I designed a custom tank to go behind the head for the shortest lines
possible. I looked for Poly tanks, but could not find one that would fit as desired, so I designed one on CAD, did a mock up with the paper backed foam board and packing tape, then taped heavy poly plastic to it and started adding layers of glass and resin, 10 layers total. ( 3/8" thick)The top access hole was cut and the insides were stripped out and the insides finished. The insides were sanded and then epoxied with a smooooth coat and fillets in all corners. ( easy cleaning) I installed with the heavy vinyl hose and redid the woodwork. I was selective on Ebay for the epoxy
and cloth always looking for the best price/ deal. The plywood was from the stove
slide out shelf project. A couple of pics from verifying fit and finished installation. I had to extend the woodwork outward slightly to pad the tank, an after thought...... ps, over 3 yrs since installation, no odor issues, works great, improved the wife approval factor.