I have two author shape pipes, a Peterson Kapet and a Luciano. Both have middle size bowls and fairly broad
bits, not narrow. Since I like the shape, I always watch for them, but they aren't so easy to find. There's a lot
more availability and variety in apple shapes for example, and more smaller ones available. Given your
specific needs on this, I think I'd try to shop in person for it, phoning around first ... if that's possible where
you are. I think bits have become broader, maybe because this spreads the weight of the pipe more evenly
across more teeth when it's being clenched. My narrowest bits are on my oldest pipes. If you are not where
you can shop in person, you might try phoning online sites and see if you can find someone to take an interest
in your needs here. You'll find it, but it will take some work. Good luck.