There are many tweaks for obtaining the perfect reforge, to get as low as 5% hit rating and trying to obtain the maximum crit chance. Notice that this is for hunters, wearing the Tier 1 Cataclysmic Gladiator (Arena season 11) gear.
Also, this is not counting the epic gems from the arena vendor that can be bought using conquest points.
The main stats, agility, crit chance, mastery, haste. The hit rating items should be all reforged into crit chance so items with other stats (not crit) to be reforged into crit.
Also this season, hunters should wear the PVE shoulders and legs to benefit from the set bonus (twice the amount of focus regenerated by steady shot).
Here is the reforge for obtaining 5,12% hit rating, 31,33% crit chance.
Head. Reforge mastery into crit.
Necklace. Reforge mastery into crit.
PVE shoulders. Reforge haste into hit.
Back and chest, no reforge.
Wrist. Reforge hit into crit.
Gloves. Reforge hit into crit.
Belt. No reforge.
Legs. Reforge mastery into hit.
Feet. No reforge.
The hit rating ring. Reforge hit into crit.
Reforge the bow from crit into hit.
Using the epic gems from PVP, the two orange gems should be replaced in order to get +10 agility and +10 crit chance. Also the belt +40 extra agility with the green epic gem, +25 hit and +25 resilience. After that, the bow can lose the crit into hit reforge.