Help please. :)

I'm having a hard time choosing my equipment (armor only {helms, shield, and armor plate})
So far my choices have come down to these 3:
1.) Spiral Demo Helm - chose it for its extra elemental defense
2.)Plate Shield - chose it for the very high normal defense and health increase
3.) Cobalt Armor - I have no idea why I chose this, I think because it looks cool. :))))
Suggestions pl0x? :)
Any armour is fine, but consider a set with getting bonuses for your main weapon as well as shield defense against Normal + Elemental damage, since those are the types you'll be shielding against the most.
Though it doesn't really matter either way. Any set that has a 5* upgrade will protect you well enough.
If your goal is to beat Vanaduke, get things with elemental def, normal def, and fire resist.
Currently, yes, the owlite shield is one of the best to get. Another good one is the stone tortoise shield and its upgrade because of the maximum health value. The shield lets you take at least two hits in even the deepest parts of tier 3.
By the way, I also chose the Plate Shield for its awesome 5 star descendant the volcanic plate shield.