Keep the balance the same (or even boost axis a bit) but remove all the USN stuff. No carriers, no TBMs, no F4us, no F6Fs. P-51s and P-47Ns and maybe (?) P-38s with B-24 and B-29 missions. Defenders do just that, defend. If done that way, the axis will NEED all their numbers to impact the B-29 swarms.
Here is a few examples of Math I did pre-frame...
Using the Minimum numbers we have 131 Allies Minimum... Subtract a Maximum of 24 B-29s. That leaves 107 pilots not in B-29s. 24 x 3 = 72... So 107 + 72 = 179 Minimum Allied Aircraft against a 183 Japanese Minimum.
This doesn't include the Allied JABOs or TBMs (TBMs Not used in Frames 1 and 2) and the Ki67.
Using the Max Numbers now... 187 Pilots - 24 B-29s = 163 + 72 B-29s = 235 Max Allies vs 258 Max Axis. Once again, not factoring JABOs, TBMs or Ki67s. In frame 3, The B-29s were upped to 48. That makes 144 B-29s so that would make 251 vs 183 MIN or 307 vs 258 MAX.
It would have been curious to see the results of a more spread out attack with the upped B-29 numbers we had in frame 3. I'm guessing the results would have been similar to the first two frames with heavy B-29 losses.
We'll see next time around I suppose.