Okay, I know all of the supposed problems and cautionaries and reasoning behind what passes for RV toilet paper but there has to be something better than the stuff that is out there now branded for RV...
Believe me if the RV toilet paper manufacturers thought they could get away with it they would sell RV stool softener pills too.
Use any toilet paper you want along with a fair amount of water.
As for putting the toilet paper in water to see what it does...put it in there for 24 hours and see what it does. Especially with a bit of Dawn dish soap which I add to my black tank every time after I drain it.