Having see a few diamond cut refurbs recently at my local refurbisher, my summary is as follows:
I'd stick with diamond cut on the Santiagos I don't think they lend themselves that well to being a full single colour, and can look cheap when done so. If I were doing it I'd have diamond cut with Aston martin sparkly grey replacing the gloss black, same with Brescias or Cadiz alloys. I'd definitely ask your refurber if they can do a two-tone paint with silver on the front and grey on the back, at least you get half your desired look.
That being said I did see a nice set of Santiagos done in a standard Pretoria gloss grey colour and it did look well against a white car.
I'm a fan of diamond cut alloys but dislike their durability hence why I've always removed mine before they got whiteworm for painted alloys or refurbed them a full colour for winter use.