Once you dilute the Xtol to 1+1, the shredded-tissue stuff goes back into solution and it's all good. It's not good to use as stock because you'll get dense spots on the film.

I use the bag-in-box method, though I just buy a 10L box of drinking water (low iron, unlike our tap water), use that to make up the developer and put it back in the bag.

There is some oxidation in a sealed container due to oxygen already dissolved in the water. You could boil the water first to degas it but I just make my Xtol up at higher concentration (1.25x, i.e. 5L pack into 4L), which reduces the O2 content by 20%. I think I've seen a report on APUG that it will dissolve in 3L.