The rafters are 53.25" long. I ripped them 3/4" square on my little table saw with my skinniest blade.
Then I rounded them with four passes of a quarter-round router bit.
I did that using an improvised router table, screwing the router to the underside of a board with a hole in it for the bit. That work made a lot of sawdust and noise.
Octagonal would have been fine. Square with blunt edges would have been fine also.
Then I moved the fence and used the same router table to taper the end down to 9/16"" to insert in the holes in the smoke ring.
Then I drilled two 1/8" holes in the other end of the rafter and added a loop of cord through the two holes. I tied the loop over a lattice stick to get it the right size. I melted the ends to blobs to keep the knots from sliding off. When I varnished the whole thing I varnished the loop also.