Barbarian wound is most useful against titans, Grimm is the most versatile of the Ramming Pulverizer Trio, my Grimm 4*+15 is going all defense & HP to maximum Total Damage Output before death and how many times per battle Grimm can use the insanely over powered defense debuff called Ramming Pulverizer ( defense debuff -10% better than attack buff +10% because defense is non-linear).
My Ranger Tiburtus 4*+15 is also going all defense & HP since penetrating defense buffs is the same net effect as a defense debuff on the enemy. So IMPROVED Ramming Pulverizer.
Since Barbarian Gormek 4*+15 is used mainly against Green Bosses/ Titans, I am going ALL ATTACK ALL THE TIME, since I can swap in Ranger Tiburtus 4*+15 if I need a tankier Ramming Pulverizer.