Re: How big a holding tank vs. camping
Yes, speaking of easier on the plumbing, urine + salt water tends to crystalize out salts, which then constrict the hoses and make it easier for things to catch and jam. Fresh water flushing cuts down on the crystal growths, too.
For anyone without a watermaker, it might be a burden to carry the extra fresh water though. For anyone who likes to Rube Goldberg, it might be a good use for storing gray water and then using that as a compromise flush?