I farmed What to Believe In a while ago with a friend and we wouldn't get drops when trying for Johanus' break with Fine Spears. This was probably back in November when it first happened. I'd think it's definitely the secondary weapon.
Either way, you'll likely end up going with Temporal/Master or Temporal/Stigma on the chest piece. I'd just go Master since it won't break your item, and you won't need a rune to protect it, unlike with Stigma. The stat difference is negligible, most important is the 5 crit on the scroll. If you go full regina(plate), reinforced/echoing and Memorable/Expeditionary are the scrolls you want for the rest of the pieces.
If you go Terminus Sentinel(Light), Enlightened/Enthusiastic, Enlightened/Declarative, or Enlightened/Journeying are the ways to go. If you find yourself over on balance with the light armor set, you can use some of the extra balance to get a Fast ES for an accessory or a Deadly ES for more crit.
If you mix the sets, remember to use three pieces of each(Weapon included), so you can get the set bonus stats. Regardless of which method you use, remember that the point is to try and stat cap with the equipment, being the 90 balance cap, and getting your crit as high as it can get. 130 crit cap for season 3 raid bosses and 140 for Neamhain.