Pre-process fisheyes to improve stitchingI wanted to post this tip here in case some of you have never seen it. You will find that your stitching is much easier and more accurate if you crop your fisheye images before importing them into Panoweaver. I picked this tip up back when I was suffering the drudgery of learning stitching in PanoTools (not knocking it - it can do things that nothing else can, but it is one tough cookie to learn!) I don't remember what website I got it from, but this is one the best tips I ever learned.
For example, my images are shot in portrait mode. I open them in Photoshop and rotate the image 90 degrees. I then set a elliptical marquee of fixed size 1520 x 1520 pixels (yours may differ depending on camera resolution and image size), no anti-aliasing. Align the marquee with the circular image. It should be of an appropriate size to trim any flare at the edge of the lens and just a hair of the circular fisheye to cut out the worst of the chromatic aberration. Invert the selection and fill with black. This gives a perfect edge to your fisheye image so that Panoweaver's circle snaps right to the exact place it needs to be. I have noticed that if there is a junky halo around the image, Panoweaver can have a little bit of a hard time getting exactly the right trim circle. It does remarkably well, but being off a little and differing from one image to the other in placement can lead to a bad stitch. Since the images shot in your camera are always on the same spot on the CCD, you can save the above instructions as an action in photoshop and crop all of your images EXACTLY the same. Mine is set up so that I just click one time and all the rest including saving the copped image is automatically done (always working on a copy, of course!). Any time you might spend doing this in photoshop is more than made up for by NEVER, EVER having to adjust the position of the circle in Panoweaver and getting stitches that are closer to perfection initially.
Give it a shot; you'll be glad you did.