Interesting question, not being negative Nancy.
First to all, the reason for swapping to RX8 knuckles is reliabilty/safety, since it is well known from the Pirelli TCR class that the original MX-5 hubs are weak. Even the new MX-5 class allows and recommends the swap.
With that being said, I did see a "gain" in camber. I would put it as non-conclusive since I removed all the links and eccentrics when I swapped the knuckles. The "gain" I saw is easily achievable with the original hardware. The only way to really know is to measure both knuckles. I would be surprised if it hasn't been done.
I'm not planning on sending Greg an email tbh, that's not my goal for the car. I'll let someone else inquire and fight that battle.