Hello all, I have a brand new liner that was given to me by a friend that took their pool down. My pool is 21 feet round and I just learned that the liner is actually for a 24 foot round. I have never changed or dealt with liners (yet) so I am just wondering if anyone knows for a fact that I either can or cannot use a 24 foot liner and just cut off the excess when it is installed. Are liners completely flat or are they actually formed in the shape of a pool like they have a bottom, cove, walls because then I can see it being a problem. Would be nice to save hundreds of dollars. thanks