This is a question that is often asked because your preference has psychological implications. Personally I prefer over because the roll unwinds more even and doesn't spin.
Definatelly over the top and you always know where the end is going to be. I'm not an expert either but I am along time user, so if the experts say something different, then they are wrong, at least in my case, for I am good at what I do.
we have a 4 roll holder that sets on the floor only issue its next to the air vent and can unwind on its own and then let your robot vacuum in the room. What a mess
back when you made the post about things can get stale....this will be post with most replies....ever By the way....over the top!
Over. So I can find the end easily. Someone mentioned if you have a cat that likes to play with toilet paper, under would be better. However, that's debatable. Over Under