: the thickness
: of the boards I have access to is 11/16" thick rather than 3/4".
: Is this too thin?

Dave,

I used boards of like thickness on my first stripper. Perhaps they were easier to use around corners but you will certainly have to fit more strips. You can see from the picture of my foredeck that after beading and coving that you only add about 1/2 inch per strip and therefore will require many more strips to complete your boat. Probably about 15% more. That's 15% more work and 15% more time spent. While I am very happy with the way my kayak is turning out I really wouldn't want to use the narrow strips on the whole boat again. Your choice of course.

Kyle T