Not to circumvent any worthwhile advice with experience here, but you may want to contact Wilwood directly to see what they advise. I spoke with a Wilwood rep on the Hot Rod Power Tour this summer, and he was very familiar with the hub and brake set up that Unique uses and even had one there to show me. While you may not be able to speak with the same person I spoke with on the tour, there are probably other folks there familiar with what Unique uses and more specifically which pad material would be an upgrade to what you may have. And of course the folks at Unique are always willing to help out and provide information from their own personal years of experience with Wilwood brakes.
As a side, here is a great primer on brake pad material with information on brake dust appearance.
Tech 101 – How to choose the right brake friction material | Hemmings Daily