Measuring the Cobra Unit Magic Acc Set Bonus

[Zaliek]

After some through searching I've come up empty-handed in regards to the amount of magic accuracy obtained from the Cobra Unit Set bonus.
According to ffxiclopedia the set bonus is an additive effect based on the number of pieces you currently have equipped.

I'd like to be able to figure out specifically how much magic accuracy this set bonus gives. What I need help with is links to information or guides on how to test and measure magic accuracy.
Google wasn't much help with this, but I'm fairly sure there must be a method. Hopefully I can get good enough results to say how much of a bonus each piece of equipment gives!

[Massimo]

You can cast 1000 spells, on the same day, on the same mob(level too) with the same gear, and do that with each cobra piece added, for another 1000 spells per piece.
This might have a slight chance at maybe giving you a clue as to what the magic accuracy bonus could be.

Good luck.

[Kaylia]

Just pretend it's +2 per piece. Square enix set bonus always suck.

[Belgaer]

It's 0 for the first piece, 5 for 2 pieces, 10 for 3 pieces, and 15 for 4 pieces. At least it seems to be after using them. Although I have no conclusive evidence other than that. :/

[Massimo]

=(((((((((

[Thorny]

It's 0 for the first piece, 5 for 2 pieces, 10 for 3 pieces, and 15 for 4 pieces. At least it seems to be after using them. Although I have no conclusive evidence other than that. :/

No offense, but how can it 'seem' to be such a specific quantity?

[Zidiane]

Thats prob based on the Iron ram set bonus.
First = zero to alignmets against ele.
Second = 5
Third = 10
Forth = 15
Fifth = 20? (We'll know when body comes out)

I doubt it'll be as high as that for M.acc, but it will follow a similar patern. Maybe 2 or 3 (Might even be 1 lol, it is lv 68 gear after all)