I think the Wildcat and Zero are fairly evenly matched if you fly them right. They are certainly both survivable. I think the Zero is likely the better plane and in a true 1 vs 1 fight at co alt, I think the Wildcat pilot would have his work cut out for him. The key is to not ever allow yourself to get in this situation. Captain Jimmy Thach proved that the Wildcat operating in pairs can handle the Zero fairly easily. With an alt advantage you can control the fight as well. On the other hand, if you are in a Zero, you can usually foil the shot of the Allies until they are frustrated enough to start turning with you, then they should die.
The first night I flew in this setup, I entered to find that there were 5 allies and only 1 IJN. After a few missions as Ally, I started to feel sorry for the poor Zeke that the 6 of us were competing to vulch, and I switched sides. I rarely switch sides to even the numbers because I am in an Allied squad, but this seemed to be the right thing to do this time. I was stunned by the dogfighting ability of the Zero. I shot down 2 enemies on my first hop, 4 on my second. On about my 4th mission, I landed 8 kills. Most of these were against Wildcats, although there was the occasional P-40. At the end of the night, I had shot down roughly 25-30 enemy aircraft, and only been shot down maybe 5 or 6 times.
Tonight was our squad night, so I was wondering how I would fare against the seemingly uber Zero. To my surprise, I shot down 6 enemy aircraft on my first hop of the night, including 3 Zeroes. Minutes later, on another mission, I shot down 2 more Zeroes and got assists on 2 others. In 3 Wildcat missions I flew, I landed all safely (except for 1 CTD).
My point is, you can survive and get kills in either aircraft if you fly it correctly. In the Zero, never stop manouvering, conserve your cannon ammunition, and dont let target fixation get you. Good marksmanship, and the ability to manouver well in a tight low speed dogfight, will get you kills. In the Wildcat, dont let your speed decay, get good at crossing snapshots, and always have an escape route. Dont try to turn inside a Zero, and be ready to extend when you can. Try to engage with at least 1k of alt advantage, and work with a wingman.
If you dont break these rules, you should survive. The problem is its awful hard not to turn with that Zero for just one more second to get the kill on him, or to break off that Wildcat you are about to kill just because his wingman is saddled up on your 6.
As far as the numbers balance thing goes, I have seen both sides with numbers advantage. It ebbs and flows, and there is really nothing to be done about it. Enough people usually switch to make things work, so its not too bad.
