I don't collect MkII's, but do collect the old style, aka MkII style, 22/45's.
There were 10 different models. My goal is one example of each, plus I have a consecutive 3 digit NIB pair of KP512's. So my main collection of safe queens is (or will be) 11 guns. In addition to that I have four 22/45's that are modded and are my range .22's. Two of the four go to the range every time.
Other than the overlap between the 2 groups and the consecutive pair I do not plan to keep any duplicates. The only reason I have, and it has worked out well, it to have trading fodder on hand when something I want comes up. The only duplicate today is an extra P678GC, which I hope to trade for a KP678GC this weekend.
Once the collection is filled out with the 11 guns, I will try to "upgrade" a few examples with NIB or nicer models, but will part with or demote the "lesser" gun to the shooter pool depending on what it is.