On the North of Ireland opting out Jim - it is all here, maps, dates, and land mass:

Northern Ireland Opts Out

Pay particular attention to the Light and Dark Green areas of the map that represented the Irish Free State on the 6th December 1922, then compare that to the Dark Green area of the map that represented the Irish Free State on the 8th December 1922.

Pay attention to the detailed land mass of the Irish Free State until the 8th December 1922 [32,433 sq miles] and then the figure for AFTER 8th December 1922 [27,027 sq miles]

Negotiations took about one year so, so much for your three day ultimatum crap. The war that Lloyd George referred to would not have been a war between Great Britain and the Irish Free State it would have been a civil war in Ireland that would have pitted the Nationalist/Republican South against the Unionist/Loyalist North.