Really depends on if we want it to be performance based alone, or useage based.
For performanced based, here is what I would do:
A6M5: 25 (face it, its simply not on-par with fighters like the Ki-84, 109K, etc. Even putting it at the same level as the 190A-5 and G-14 is quite a strech)
109K: 18
B-239: 25
110G: 23
F4U-1: 23
190F-8: 30 (based on current ordnance packages. Would be dropped to 28 or even 25 if those were expanded)
Hurricane IIC: 10
Hurricane IID: 30
La-5FN: 20
La-7: 5
Me 163: 4
Me 262: 3
Me 410: 25
Mossie: 25-27
P-38J: 15
P-38L: 13
P-47D40: 15
Seafire: 20
Ta-152: 15
Typhoon: 12