The George (N1k1, and N1K2) faught in several Battles during the later part of the war from mid 44 till the end( first action for them was during the invashion of the Philipines). Including Okinawa whear it flew escort mishions for the strkies aganst the Allies their, Just one of the George units in operation hear Air Groupe 343 in operations around Okinawa scored aprox. 106 kills with the loss of aprox. 29 Aircraft.
The George can also be viewed as a stand in for many other late war Japanes fighters we dont have in AH that were operation during this time many of which were in action over Okinawa.
Skining a Russian fighter that in no way preformed anything like the Ki 84 and had a very different gun package, would not be somthing I would realy go for, espichaly since it would likely see a lot more use than any of the Japanese planes which we have.
The Flack, issue has to do with the number of guns on the fleat that are producing it, adjusting the lethality will not decrease the Flack buff's, we treyd this before, and it did not help. The best way to reduce the Flack from the fleats is to sink a few ships outa them:) The Field ack is no problem it is easly taken out, as evidanced by the very fluid front on Okinawa, realy the clusters seam to make the guns easer to kill. espichaly if bombs are used aganst them.