PaizoPathfinder Flip-Mat: Basic

How long can you leave wet erase marker on this mat before it stains? I'm looking to draw maps ahead of time when possible.

Is this made out of cardboard or like a yoga mat material?

What are the dimensions of the mat (width and length)?

If i get all the creasing flattened out of these, can i safely store them rolled up? i'd rather deal with some curling than giant creases...