Like a weekend at a casino, make sure the expense is money you can spare, and don't do it to make money.
I just got a similar CD as a gift from one of the folks who put it together, and his observations might be valuable to you. The CD (Harper's Retreat, part 2) was made from a weekend of singing; there had been a CD made from the session the year before. He noticed performers "playing to the microphone" instead of sharing with the audience, and it showed. He also said it was a good idea to have someone listen to the prospective choices who was not at the actual performance. Sometimes our ears hear what we remember experiencing, rather than what actually went on the tape. I hope this helps. I enjoy this type of recording, and I'll often buy them, but I'm a few thousand miles away.
Good luck with the project, Mary