Many people are playing custom Virtual Console versions of Pokemon Gold, Silver and Crystal. The saves of these games cannot be easily edited with PKHeX though, since  PKHeX expects a different file size for Gen II saves. Direct support for these kind of files will surely be added by Kaphotics someday but in the meantime, you can use this converter right here to easily modify the size of your save file so that it can be used with PKHeX. It also works the other way around of course so that you ca