No actual examples
I was just trying to picture in my mind how wide the ones I’ve seen are. Maybe five inches isn’t something I’ve actually seen. I’m sure I’ve seen kneeling thwarts that were four inches wide though.
Good advice
The guideboatguy has good advice.
You can paddle a tandem from the stern seat as long as there’s hardly any wind and the water is like glass. Otherwise, you’re going to have problems.
Paddling from the bow seat (facing toward the stern) can work, and lots of people do it. Kneeling in front of the bow seat might work better yet. The problem I’ve have with these approaches has to do with canoe dimensions. Solo canoes are typically narrow at the gunwale, making for an easy, natural stroke. Tandem canoes are usually wider, and I’ve had problems clearing the gunwales with my (not very long) arms.
My advice is to get a solo canoe if that’s the way you plan to paddle.