Someone has been watching The Princess Bride, I see. ;)
I dislike both names, but would choose Westley if forced to choose under pain of death. No thanks to the character by the way, I thought he was so full of himself. It's just a bit more of a "discrete" name than Iñigo: less loud, more sophisticated.
As for a middle name: I think Ambrose would fit nicely with Westley.
Forchta in biuonga quamon ouer mi, in bethecoda mi thuisternussi.
In ic quad: "uuie sal geuan mi fetheron also duuon, in ic fliugon sal in raston sal?"