Keilau, I just need to ask, are you absolutely sure that about the relevance of the angle of the needle? Proof that it matters more than nozzle size? Because I have my doubts about it. Not that it's irrelevant, but as with most things, one of many contributing factors. Others than nozzle size and needle angle might be nozzle outside angle, surface polishing of the needle, nozzle inside polishing (though I doubt it) nozzle cap design, needle cap design, air feed channel design, paint channel design and so on. To isolate one or two things as what determines performance, might be making it a bit too simple.
And maybe, how do we define performance? Is it detail capability alone?
I'm not saying that you are wrong, but sometimes things can't be explained by one single factor. And sometimes things are the opposite of what you think is logical.