This thread might interest you, you’ll need to do a bit of custom jigging to get the goblet properly flat unless the diameter of the foot is the same as the cup portion.
As an alternative, how about engraving on adhesive back veneer and wrapping it onto your goblet? If the goblet is being custom turned they could engrave a shallow band matching the thickness of the veneer so it could sit flush with the surface and look cohesive.