The main purpose of the tags is to connect related sets. If a tag is set for almost all sets, it does not help to select related sets. So, it is best to use few tags that are highly relevant to the set. Windows XXX should only be used then the set has a special relation to that Windows version -> in very rare cases.
512x512 is not a valid size for Windows .ico files and .ico files with such images are invalid (there may be Mac .icns icons with this size). The web probably would not work correctly, if you tries to upload .ico with 512x512 image (please don't try that).
When selecting sizes for icons, I think, it is best to only stick with the standard sizes: 16, 24, 32, 48 and 256 and leave all the others out. For color depths, I would recommend 32, 8, and 4 bits. Not 24 or 1. An alternative is only using 32 bits - everybody is using truecolor displays these days anyway.