I also have a free-form IG pool. I bought a solar cover and decided to cut it so that it fits perfectly on the water. It fits well but is a major pain to work with (the fact that it doesn't make much difference is all the more frustrating - too many trees == not enough sun to warm the pool) . At the moment it's two very large pieces - next year I'm thinking of cutting it into more manageable pieces as suggested in another thread by AnnaK -
http://ellerbach.com/Pool/Solarcover/. The easer it is to use the more likely I'll be to use it.