dread skelly shield or grey owlite shield??? and.....

dread skelly shield or grey owlite shield (4* and 3*) right now
Glacius or Cold Iron Vanquisher (both are 4* already)
well here are my items try to make it match and stuff:
skolver cap
skolver coat
gran faust
Argent Peacemaker
and i want it to be good when i fight Vanaduke

The only case I take my Sinister Skelly over my Gery Owlite is when entering a Fiend stratum, apart from that Owlite is much better.

Grey Owlite: best overall T3 shield (fire, shock, good elemental defense for turrets; also does well against Vanadork)
Barbarous Thorn: best overall sword-user shield (medium damage bonus kicks butt)
Volcanic Plate: best anti-Vanadork shield (high normal, stun, fire, good health)
Crest of Almire: best anti-Fiend shield (great for FSC too, but not the final fight)
I'd build the Skelly Shield only if you don't think you can get enough tokens/crowns to purchase a Crest.
Grey owlite shield. It's even better in FSC because of the Fire resist. For FSC.. I'd upgrade to Glacius first.