Businessman by day, butler all the time.
Formal dresscode - three piece suits, white shirts, double cuffs, silk ties in double Windsor knot and all the needed accessories - white gloves, cufflinks, pocket silks, pocket watch and chastity cage.

Yes, chastity is quite important, as it helps servant focus on the more important tasks and less about his phisical pleasure. The servants pleasure comes from the service itself and from the Dominants pleasure.