You'll get a good amount of stretch in a jmold liner, on my 30 foot pool, I built up a 3" base of screening s for teh wall to sit on, and the sand in teh pool is even with the base rail - however, I sloped it down towards the center, so teh middle of my pool is actually 8"-10" deeper - could have gone more, but didn't know that before the install - I really don't think 2" matters here or there...