[Buckmazter420]

I've read several forum's on here, and other sites unrelated to Ibanez, but I came here for an answer because Ibanez. So I've found 4 mixed answers.
1) Measure the width of the nut.
2) Measure the neck behind the nut.
3) Measure the neck in front of the nut.
4) measure the distance from E string to E string.

So what is it?

 

[jemsite]

1) Measure the width of the nut.

The locking nut width refers to what size neck - at the nut open fret - it fits.

A 43mm nut (yours) fits a neck that is 43mm wide at the nut.

 

[sepulchrave]

...So I've found 4 mixed answers.

There are two correct answers when it comes to Floyd Rose systems, 42mm and 43mm, I'm not sure where in that towering wall of text the correct answer is buried but you seem like a smart boy...