Maximum Magnitude

[Salem Verano]

Hi all,

I've had this ring I made for years now, 'The Featherweight' Feather for xxxx points and Fortify Magicka 1000 points.

Now I change the value of the feather magnitude on occasion, depending when I need it.
So now I was wondering what the maximum magnitude setting was for feather, without messing up the game ?

Greetz,
Salem