We did a private tour with Roaring Tours,
https://www.roaringtours.co.nz - Nathalie is a trained sommelier who has worked in some of NZ's top restaurants and has great contacts with Otago winemakers. Not the cheapest but better than some of the tours we had in other regions where we went to less inspiring wineries. She will chat to you about what wines you like, and will only finalise your itinerary based on your reactions to the first winery, as that will help her identify which wineries might be to your taste...