I have printed 44" by over 20 feet (6+m) long.
These prints were looked at on the floor, but gallery hung with nice large chrome headed pins every 60 cm or so.
With more manageable beasts, say 44" x 1.5m, I have some foam boards about 1x2m by 5cm thick, that I use for reflectors in the studio.
The big print are ejected down onto a board. When out, galvanised nails are pushed through the 4 corners of the print, and sometimes on the long edges, into the board. This is done outside the stroke maks that delineate the border, so the print , when trimmed, is not damaged.
The print can them be lifted into a vertical position for protective spraying, and left for inspection for as long as required.
HTH
Brian
www.pharoseditions.cm.au