Governor General vs Viceroy: A pressing issue

At a recent soiree, one of my delightful dinner companions posed the question: "what is the difference between a Governor General and a Viceroy?". Having dealt with this question elsewhere not long previously, I was amused to see that it continues to perplex those whose feet are firmly planted under a decidedly modern Ikea table. Such questions are far more enriching than wondering which car insurance firm supplies the best deal! To spare other suburban homes the misery of sleepless nights I provide my personal view of the distinction:

Whilst a Governor General is often styled the "vice-regal representative", a distinction between the offices of Viceroy and Governor General is often drawn; however the precise definition of that distinction is open to debate. A traditional view held by many places the office of Viceroy above that of Governor General, on the ground that a viceroy acts as if he were the Sovereign and not merely the Sovereign's representative. Many of those who argue for this distinction also maintain that a dominion cannot have a Viceroy as viceroys only exist in colonies that are not possessed of the governmental powers and legistative structures possessed of "independent" dominions. This would seem to be supported by the Irish example: the office of Governor General of Ireland replaced that of Viceroy in 1922, upon the establishment of the Irish Free State (however this oft-quoted example may not be terribly useful as the official title of the Irish governor was that of "Lord Lieutenant"). To substantiate this view one might also evidence the high degree of pomp, protocol and ceremonial associated with the court of a Viceroy compared with that of a Governor General.

India provides further evidence that the two offices are separate and distinct (at least in a sub-continental context): the Viceroy of India was simultaneously Governor General, the official title being that of: "Governor General and Viceroy of India" (or vice-versa). It is my view that the distinction drawn here is between that of the King-Emperor's representative in India (Viceroy) and the chief administrator of India (GG). This distinction seems to be supported by contemporary Court Circulars such as that issued at the time of the Delhi Durbar; here, during a Council held by King George V in India, his representative in India is styled only as "Governor General" and not as "Viceroy". This draws me to the conclusion that the presence of the King rendered the position of Viceroy unnecessary and therefore the Viceroy and Governor General could function only as GG (chief administrator).