I made Black-Walnut hull tincture in October every year for several years. I had to stop when my favorite spots got sprayed for West Nile. Hulda Clark said to use the large (liter, I think) bottle of Everclear. It's been 20 years since I read her book, but as I recall she gave some reason for using the larger size that had to do with the larger bottle containing less of the (?) antiseptic that all those liquor bottles are cleansed with.
Three days of soaking the green hulls was Hulda Clark 's recipe. She said they had to be green hulls to be effective. I tried to use the prettiest, unblemished, bright green hulls that I could find. I would label my bottles as "first quality", and then on down the line, depending on the state of the green hulls. I used wide mouthed glass jars. I think they were 5 gallon.
The Walnut trees I used were not the legitimate Black-Walnut . They were Texas Walnut. But my tincture still worked. I loved making this useful product for myself. The pinch of vitamin C kept the tincture green and potent.