There all kinds of different tapers on needles. Although I never seen anything like you are talking about. But bottom line is a bigger carb will take away low-end torque and all the needle mods in the world will not get it back. If it was that simple all the little bikes would have big carbs with funny needles.
I'm not saying there should be capital punishment for stupidity, but let's take the safety labels off of everything and let the problem solve itself.
current bikes F800GS-WR250F-Versys-690R-RZ350