I'm not just a stinkpotter up there. I used to cruise around on a Shark and a Hobie 18. My brother and I used to sail to Midland for pizza, me in a Laser and him on a windsurfer!
Unless the Tomb and Cedar Point are having that big an effect, I have to disagree on the winds. They used to be more out of the W and WNW but have shifted more WSW in past years. In terms of strength, I don't know what's happening. Here in Toronto, winds seem higher than they have in past. At the cottage, they seem lighter. We used to get (more than 15 years ago) some really good 3 day blows (sustained winds over 25kn) at least 4 or 5 times per summer; not anymore. We also don't seem to get a seabreeze effect anymore. It used to be you could count on it. Our Saturday morning races would have ghosting starts but by the time you started your final beat to the finish it would be blowing 10-15. Shifting high pressure systems?
The reason I was recommending the outside route was Dave's objective for the trip is to spend time with friends IN Killarney, not getting to Killarney. Otherwise the inside route is the way to go. I love the ability to pop around into almost any little bay and be able to drop the hook, swim and fish. Real fishing; muskie, bass, pike and pickerel (walleye to the US).
In terms of depth, I have also been watching the lake levels. Not just for sail but for power as well as it affects my fishing holes
. The Bertam draws only 2' (3'6" at speed) and the outboards (both of em) need only 2'6" at speed, but the Northstar draws 5'3" unloaded. I like to give her 6'.
Waves at O'Donnels Point are on a direct line from Huron and their size IS in direct relation to the combined fetch of Lake Huron and Georgian bay. It's like that old experiment of light going through a pinhole. As the waves pass through, they expand concentrically outwards. It just happens that as the wind is blowing at the same time, it will force the waves back to their original direction.