When deciding on an FSC shield people usually only consider the boss fight itself. This is because after becoming familiar with FSC you don't even need to shield that much prior to the boss fight, you just get used to fighting swarms of Zombies and charging Trojans. For Vanaduke though, you are looking at mostly Normal, Elemental, Fire and Stun which is why Grey Owlite Shield and Volcanic Plate Shield are so popular for FSC.
Dread Skelly UV Elemental High, despite being High, isn't going to increase the shield's element defense to anywhere near Grey Owlite. It also doesn't defend against the Fire or Stun statuses so any attack containing those will hurt the shield quite a bit. If I had that shield with that UV I'd still bring Grey Owlite.
When deciding on an FSC shield people usually only consider the boss fight itself. This is because after becoming familiar with FSC you don't even need to shield that much prior to the boss fight, you just get used to fighting swarms of Zombies and charging Trojans. For Vanaduke though, you are looking at mostly Normal, Elemental, Fire and Stun which is why Grey Owlite Shield and Volcanic Plate Shield are so popular for FSC.
Dread Skelly UV Elemental High, despite being High, isn't going to increase the shield's element defense to anywhere near Grey Owlite. It also doesn't defend against the Fire or Stun statuses so any attack containing those will hurt the shield quite a bit. If I had that shield with that UV I'd still bring Grey Owlite.