For most cases, Skull Cap + TSoD > OBMH + Crimson Rod. For High MDEF monsters from the Brute, Undead, Formless and Demon races, the OBMH + Crison Rod > SC+TSoD.
If you don't need a shield, OBMH + SoD >> SC+TSoD.
You'll need multiple hats, though. Ideally one with Red Lichtern, one with Yellow Lichtern and one with Tikbalang. These cards also go nicely in mid headgears, if you can afford them all.
EDIT: This is for Warlocks only. For Sorcerers it may differ, because they don't have Recognized Spell, nor MA, so there's little difference if the MATK comes from Weapon or Equip, and Crimson Rods/Staves have very high Equip MATK (if highly upgraded, of course) and very low Weapon MATK.
Edited by Kusanagisama, 28 November 2016 - 10:18 AM.