I think for your first trip it would make sense to stay on the north side of Manitoulin. I have spent a many many weeks in the North channel and do have a desire to see the ducks but not sure it is worth your hassle just yet.
I prefer Rattlesnake to Club and from there it is an easy day to Little
Current. Fog tends to be an issue in Georgian Bay proper but not in the channel.
Heywood is a decent over night stop, you can go back quite a ways in the channel. Once you are past Little Current you could stay along the Island to Kagawon, Gore and Meldrum bay then head up to the Whales Back Channel which I highly recommend. Then back through Little Detroit , the Benjamins, Croker and Baie Finn.
Baie Finn, Covered Portage, The Benjamins and Killarney will be very crowded from about the second week of July to mid August. There are however still some not very well known spots to anchor and enjoy.