PDU off or on is a big deal....but general advice good for either:
Put 10 factories each sized to 30 on each the Sam and Frank A. Look at all your r&d facilities and pick those that are researching oddball planes, especially non-fighters that won't arrive until 1945. Bar none, these two fighters are the most important planes Japan researches...
I have no idea if you are playing PDU:off or On, but I think that you will find it impossible to dedicate 10 factories to Frank and the A7M2 for PDU:off. That is 20 factories. The problem is that, in PDU:off, you cannot upgrade any squadron out of sequence. So, in order to upgrade to Frank, many squadrons must first upgrade to Oscar IIIa. Advancing Frank to April 1943 is of little benefit if you must wait until 1944 for the Oscar IIIa. The same can be said for the Sam. In order to upgrade to Sam, a squadron must first upgrade to the A6M8. In order to upgrade to the A6M8, it must first upgrade to the A6M5c. In order to upgrade to the A6M5c, it must first upgrade to the A6M5b, and so forth. There is no skipping steps.
Because both the Ki-43 and the A6M lines must move through multiple airframes to reach their conclusion, you will need a good number of factories on these: 4 on Ki-43, for example, and 8 on A6M. If you were to combine these 12 factories with 20 for the Frank and Sam, you will find that you have few, if any, factories left to advance lines such as the Tony, Tojo, Judy, Jill, and the Nightfighters. Tony and Tojo will account for nearly 40% of your mid-late war airplanes, so it is helpful to have some R&D in these as well. Also Judy is very important, because the Val's small 250 Kg bombs will not penetrate thicker armor.
Again, this is for PDU:off only, but much of the same can be said if you are playing PDU:On and do not skip steps: which is to say, advance your R&D directly from the A6M2 Rufe, for example, to the A6M8. If you are playing PDU:ON, and you intend to skip steps and have 8 fully repaired factories researching the A6M8 in March of 1942, you should probably speak to your opponent about this in advance. I think many allied players would be very alarmed to see 1945 airframes appearing in 1942. The same can said for the Ki-100 Tony, which can also be available in large quantities in early 1943 if you skip steps and invest heavily in this plane.