Does not matter because this was just an issue of a military fortune. If he won, he would end with two electoral positions.Well three Catholics bishops and one Catholic King were more than enough for preventing the election of a Protestant as Holy Roman Emperor. Plus Habsburgs were Catholics and the only not Habsburg HRE after the Reformation was still a Catholic Elector, son and husband of two Austrian Archduchesses so...
Frederick of Palatinate was never recognized by the Imperial Diet as King of Bohemia and was soon deprived of both Kingdom and Electorate so his double vote was never a problem (at the election of 1619 the other prince electors recognized Ferdinand of Austria as King of Bohemia instead of Frederick, who was elected and had accepted but was not yet crowned as King because Ferdinand was elected as heir and the prince electors considered invalid his deposition by the Bohemian parliament)