@pghaworth: You can just install Python right now, no need to uninstall/reinstall anything, it won't be terribly different (the first run of the Python scripts will just be slower).
Note that in the ScreenSavers Hack's case, it's only needed for the cover mode. (And that you'll need the latest snapshot version for it to work at all on FW 5.6.x).
Keep in mind that you can just chuck everything in one go with the MR Package installer, and it'll take care of everything, mostly in order

.