"Fw 190 Aces of the Western Front" (Weal) states that the second Gruppe to receive the Fw 190D-9 was II/JG26 and they did so in December 1944. The first Gruppe to get them was III/JG54 and they flew them into combat in October 1944 protecting Me 262s bases after receiving the new plane on strength some time in September. So I don't see how we get 500 in action in mid 1944. In fact it would appear that JG54 is it in November 1944. 3-4 Staffels max.
"Bf 109F/G/K Aces of the Western Front" (Weal) states October 1944 for the Bf 109K-4. My understanding is that the Bf 109G-10 was received at this time as well. I get the comments re the stand-in for other Bf 109G types and I don't disagree. The exact #s mix is a design call.
Those sources for this kind of use is a poor choice at best. These kinds of sources are additives to your knowledge. "Fun to read", learn more about pilots. In no way should they be used to write an FSO or any event besides Snapshot.
Your first sentences about the FW 190 are a little off. III/JG 54 were the first to get them. They were flying cover for Kommando Nowotny, but only half of them. The losses prove this. I/JG 26 were the second to get them, not II/JG 26. As of December 31, 1944 there were 183 FW 190D-9's in operation on the Western Front. Some 65 or so with the MW 50 installation.
In conclusion, I believe the D-9 deserves a +10 on its maximum. The 109K-4 at 48 max should be fine. In turn, you may consider raising the minimum of A-8's if you feel there is a balance issue.
Spencer, Jay P.
Focke-Wulf Fw 190: Workhorse of the Luftwaffe. Washington, D.C.: Smithsonian, 1989.