Unless you have a capable helper, don't even consider using anything longer
than 4x12. Even that can be a b*tch to handle. 16 is way too long for one
inexperienced person to manage.

AMEN! My last job involved 4-1/2'x12' sheets to deal with a high
ceiling. 104 pounds each, the 12 footers need to be taken off the truck
in pairs. I got REAL TIRED of the 204 pound wiggly chunks of rock!