Memory Stick Decoder Ring

Does anybody possess the secret decoder ring to interpret Memory Stick labels? For instance, say I wanted to get a reasonably large Memory Stick to put in a PSP. I think the Duo format is slightly smaller physically? And Pro has Magic Gate? So you want a Duo Pro stick? Is that required? I've got this theory that I should mail order a large enough stick to put video on, and do it BEFORE the PSP releases.