How many members should ideally be appointed from persons who have held office under the Government of India or under the Government of a State?
From the context provided, ideally one-half of the members should be appointed from persons who have held office under the Government of India or under the Government of a State. This information can be found in the sentence: "Provided that as nearly as may be one-half of the members of every Public Service Commission shall be persons who at the dates of their respective appointments have held office for at least ten years either under the Government of India or under the Government of a State."