Anime-Beta TNG

So I was wondering, if I have to store portrait art portfolios like Itoya or Prat horizontally (think like how one would hang these books in hangers so the opening is facing the floor)... But instead of hanging the folders, I actually store them in a mobile cart (note no hanging involved here, the portfolio touches the bottom). How would you do it? Would you have the opening facing the floor of the cart? Or would you have the pine instead facing the bottom? Due to size I don't think I can place them portrait like how you would on a bookshelf, so it has to be landscape. Of course I could put them lying face down but I think that's horrible since I have like 10 portfolios to deal with. Thanks!

Itoyas (alone) I store like an upright book on a shelf with the opening facing the ceiling. But, for really expensive Disney pieces, I actually store them in Itoya reinforced with a heavy duty art portfolio from Pissaro (I secure the side with the opening in the larger portfolio with a valcro strap, then zip it up to prevent movement), which is then stored upright like a brief case where the handle is upright. In addition, I slide heavy backing boards between the Itoya and the larger portfolio case to prevent the Itoya from moving and to reinforce the sides from bending.

If I had to choose between the two, I'd go with the opening facing down. That way if dust were to fall on it, it would hit the spine rather than go inside the Itoya.