I like the fit of the 12" saucer better too. However, I set mine down on a cold surface tonight, and it split in half. I guess the saucer was warmer than I thought. I'll have to make another trip to Home Depot soon.
I using my 14.25" saucer now, but it doesn't fit as well....IMO it sticks up too high above the top of the water pan, which puts it too close to the lower grate. Not a problem if you are not using the lower grate though.