Try #1: Looked great, but the waistband seams didn't match up very well, and one side didn't seem sewn close enough to the zipper teeth.
Fix: Resew the one side, making sure the teeth were properly in the groove of my zipper foot. Ponder ripping out the other side to make the seams match up better.
OK. I just couldn't stand it, and I ripped it out and redid it. But:
I'm not sure if you can tell in the picture, but the resewn side is twisted, and while it appears to be sewn on correctly, when you get down to the pull you, um, can't close the zipper. There is no fix for this but to rip it out again. First, you must go eat lunch. Walking away helps.
Now it's right. Untwisted and resewn. The moral of this story: When sewing the second side of an invisible zipper, make sure it's flat all the way down and does not get twisted.