I spoke with someone at the Mansion yesterday and found out that the tasting is held during the brunch. They ask what 3 entrees specifically that you want to taste, minus the prime rib because I think they serve it at brunch. They will provide the three entrees you select and that's it. There is no sampling of the hors d'oeuvres or stations.
I assume we can eat the brunch food too when we're done the tasting.
When you walk in the lobby, tell the person at the desk that you are there for a tasting and they will guide you on where to go.
HTH