A hint for dealing with extra-large maps:
Use a knife or scissors to cut away sections of maps you do not need. Smaller maps are much easier to handle, fold, and squeeze into a small map case.
I have removed up to two-thirds of a map. The smaller maps are a cinch to refold, especially in the wind.
It's your choice whether to carry the excised maps as dead weight, mail them home, or chuck them.