I use the NVidia plugin with Paint Shop Pro 9...I create the images, save them as PNGs with alpha-channel transparencies, then as DDS files.
The actual plugin settings are:
- 184.108.40.206 ARGB 32 bpp | unsigned
- 2D texture
- no mip maps
I start out with a 500x500 image then increase the canvas size to 512x512 when I'm ready to save, leaving a 6-pixel margin around the edges. This is because any pixels that venture too close to the edge will turn into lines stretching out into the distance in a finished ring -- yucky.
I've done so many of them that I don't even think about the various steps anymore, but I think writing a tutorial on how to make custom rings might be something to keep me out of trouble for the next few days.