I'd best come clean. With some multi-part sites (but not Vauban nor Le Corbusier) I have applied my own criterion rather flexibly and allowed myself to count a site if I have visited enough parts of it to have seen more than half the total area of all the parts, but always with a minimum of 2 parts. I hope that's clear.
And in one case I can recall, Vicenza and the Villas of the Veneto, I developed a severe case of Palladio fatigue and simply gave up well before the 50%+1 threshold. I felt that one visit was merely repeating what I had already seen several times. What a Philistine, eh?