I have a doughboy above ground pool, supposed to be 16 x 24, 4 ft wall, but it measures only 15 x 22. Got it used. Need a liner, want to dig down to 5 ft, has 4 ft wall, Best liner to buy, 16 x 24 60 inch or 18 x 24 48/52 inches? Concerned about overlap inside of pool, could this be a problem and which size would work better?