Just because PQ in alcohol is very easy to mix and doesn't needs heathing.
I'v mixed 100cc of PQ (Patrick's staining formula) about 45 days ago, and it's clear in a half filled plastic bottle. And, the bottle does not collapses, indicating there is no oxygen absorption.
I add the alkali and sulfire when I mix the working solution (for film, borax of a stock solution, sulfite using spoon).
For paper, I intend to use spoon both for alkali and sulfite.