You'd have to read back through the many comments, I've addressed a merc question many times and can't remember how I responded besides "I didnt use a merc for this charaacter because of the constant need to move forward through mobs to lure and leech while hammers kill. Merc will lag behind and stop mobs from following and didnt fit playstyle"
whichever merc you feel most comfortable with would work fine, but I didnt use one