I use 4-up hangers for 4x5 film (it is an 8x10, 1 gallon set of tanks). I don't have issues with surge marks, but I have heard of them. I may be slow or downright ponderous about moving the hangers, though. It generally takes me 2-3 seconds to do a single agitation.
If I had 400 sheets to process at once, I'd even consider using 3 1/2 gallon tanks, but I only have a couple of those.