I'm thinking of buying a solar pool cover for our swimming pool. I
understand that these work by cutting the evaporation (there's some
useful info at
http://www.eere.energy.gov/consumer/...mytopic=13140).
But our pool is kidney-shaped, and it's not clear to me whether it
would be better to

(1) cut the cover to the shape of the pool, or

(2) keep the cover rectangular, but don't cover all the water.

Are there durability issues if I do (1)? From what I've read, it
should buy a reel to make it easier to put on and take off. I'm
concerned that using the cover every day during the cooler season would
mean that the wider parts of the cover would rub on the narrower parts
of the pool as I reel it back and forth, and wear it out (more!)
quickly.

It's also unclear to me how well I can fit it when I do the cutting,
and whether a little excess cover or a little open water is better (or
maybe this doesn't make much difference).

Mike