No clue about seat maps, but I fly that route on CA fairly often. Personally, I usually shoot for 737s because I love the bulkhead aisle (infinite legroom) and the fast boarding/deplaning, but the 330s that also fly to Australia are very nice airplanes.

In any event, you can safely cross the 772 off of your list because they are getting old. Regarding the remaining 3, iirc CA still has some 330s that are left over from its KA wet lease. These are to be avoided, if possible. I'm also skeptical about the 340 because most airlines stopped ordering those after the 330s became popular (i.e. they are probably older).

I too am curious as to how to well whether or not the 330 on my chosen flight will be great or just so-so.

Sorry I can't provide better info.