Diurnal AST+whm is possible on nidhogg but i do agree with Foxy
Having noct ast with shield to soak in some damage is priceless

Becauseit allow squishy dps to survive at least 1 more akh morn by artificially adds some hp while waiting for the cure 3 to happends
After trying both
Shield are easier and allow less stress in battle (but more mana consuming than HoT)