Reminds me, the FlaK 36's kill rings are from both tank and aircraft right?
If the 88 has a gun shield, they usually first draw, say a tank and put individual lines below it every time they destroyed a tank. Draw a plane and put up a line every time you shoot down one and so on...
They can also do with the ring style if they don't have a gun shield by designating 'zones' for every type of enemy destroyed on the gun barrel although things can get confusing once your gun has killed a hell lot of enemies of various kinds.