Couple of questions about the F4U-D in the Pacific campaign

[The Stalker]

Hi, I've been AWOL for a while from this sim only to return when I found out the 4.11+hotfix is out. I apologize if I'm a little out of the loop.

Anyway I've been playing the USN campaign trough Lowengrin DCG 3.47 beta 6 and I have a couple of questions regarding the F4U-D, the aircraft I'm using.

1) I have noticed I get a considerable MP boost switching supercharger to stage 2 even at 1000m. My rule is to switch to a higher gear if any MP is gained. Is this ok? The Flight guide says speeds should be switched to 2 at 2600m I think so I find this confusing.

2) I seem to be having trouble keeping up with the rest of my formation. I'm crusing at 90-90 PWR-PP rad closed which is pretty much borderline overheat for this plane and map (Iwo). Still, there is no way for me to keep up, the AI wingmen are always faster and in a better climb. Am I missing something here?

3) The F4U/Corsair engine seems a bit underpowered. I have trouble chasing a zero in a level flight (90-90 or even 100-90) which I understand should not be the case in this plane. Still, I'm not a great pilot, maybe an average one although I'm trying to improve, so I might be missing something, if I am, please give me some tips on better flying the F4U-D.

Thanks in advance.