Your preferences, your eye, your developing technique, your metering techniques, your normal subject matter.
You personal EI should simply be whatever gets you the print you want in the easiest way.
You might try this for a start.
I see what you did there...
"Once the amateur's naive approach and humble willingness to learn fades away, the creative spirit of good photography dies with it. Every professional should remain always in his heart an amateur." - Alfred Eisenstadt