Well , Im going to discover NOW who is Red John , so this is a VERY HUGE SPOILER

1- I have seen a photo where Reede Smith , Sheriff Thomas McAllister and Gale Bertram are with PJ but this says that they arent RJ. This photo is gonna be show on S6 E2.

So , if we count that , only this suspects are RJ-
-Brett PATRIDGE
-Bret STILES
-Raymond HAFFNER
-Bob KIRKLAND

2- Lorelei told PJ that RJ wasnt his friend since they shoked hands.So Bret Stiles isnt RJ

So now the list is - 

Brett PATRIDGE
Raymond HAFFNER
Bob Kirkland

3- RJ has 30 when he started to work on Vizualize.So Brett Patridge cant be ... he also didnt work on Vizualize.

So now the list is-
Raymond HAFFNER
Bob KIRKLAND

And the only one here that fits with all thew clues is ... RAYMOND HAFFNER. HE IS RED JOHN.