For ease of maintenance (just like Aust MVs in SVN), I'd use the semi-gloss. The colour is the same for all three, just the degree of gloss changes (at least, that's the theory). Anyway, decide when you receive the colour plates.
I forget the origin of your Cent - it's one of the ex-'Courage Under Fire' movie vehicles, isn't it?
Given your interest, you may learn a lot from Stephen White's thread on the Armortek forum about researching & building his 1/6th scale Centurion that model's 169064, a Cent that served in South Vietnam. He has gone to extraordinary lengths to get every detail right. Much of that research will be applicable to your restoration.
http://www.armortek.co.uk/Forum3b/vi...61bbce95a21fd8
Mike