My choice for Ra-Havreii is James Callis (Galactica's Gaius Baltar).
Nice but I think Callis is one of those actors who can play one character brilliantly, and not really branch out. So we would have Gaius in engineering.
Have you seen Callis in roles other than Baltar? I've seen him in one other role, as a prince in the Halmis' Arabian Nights
miniseries, and he wasn't very Baltar-like there. Anyway, Ra-Havreii has qualities in common with Gaius Baltar, particularly his arrogance and his womanizing, so I think it's a good fit. And I had Callis in mind when I wrote Ra-Havreii in Over a Torrent Sea
, so there will definitely be a resemblance in that book at least.
As an alternative, I'd suggest Alexis Denisof.