Anyone interested in 83 Pace Arrow Tear down and Rebuild?

I have been a boater even longer than an RV'er. None of my boats have had aluminum holding tanks so I have no first hand experience but the forums , as expected, have proponents of aluminum tanks and foes of them. I'd say the vast majority fall into the second category claiming urine will have detrimental effects on the aluminum and welds.
You might want to look a bladder tanks as a possibility.