Why i am confused 

How can patrick go through hundreds of suspects and know only 7 of them could be RJ?
Sorry, but I just don't think that is realistic.

I know heller said that jane isnt RJ, which I agree. Patrick jane is the character we all love. Red John is Janes other personality, which is nothing like Patrick. Thats why heller says patrick isn't RJ.

The voice of RJ in the season 4 finale is obvioulsy Patricks. http://www.youtube.com/watch?v=l_CK_90hei0

And I don't think RJ is psychic.