It's interesting how we form a context of 'big' and 'small' dependent on the material we see day to day. Looking at maps all day, an object 3 or 4 feet seems small to me :)

The maps we humidify and flatten average 10-15 feet long. We have a few over 30 feet. We use 4-6 large tables with wheels, and flatten between a sandwich of felt and hollytex with plexi sheets and weights on top.

When we have to flatten the really big ones, it seems we scavenge lab for all available weights - metal weights w handles, bricks, pieces of marble and random chunks of metal (industrial city we have these laying around, naturally).

I always enjoy your posts, thank you for sharing-
abw