Well, took two tries, but I got the final design mold printed. 16mm diameter, 120mm length. First one went spaghetti. Shoulda took a picture, it looked pretty cool lol. If you have any adhesion issues, a little glue stick helps. 
The taller it is with fewer slots, the more of an issue it becomes.
The bands are intentionally tight so that as they break in with PLA, they still stay sufficiently tight. They’re a bitch to get on and off the first few times. Some light sanding might help, but I prefer to wear them into each other.