You’re welcome, dnvie.
As I mention it here and there, modeling is like chess playing, always have the next few steps in mind.
I would start by Chamfer the Splines. In the moment the Cogwheel-Inlays fit the target, try to find a good setting for the intermediate points, then (Object-Manager> Objects> Current State To Object) from there, we have two options, one native and the other one with a Cineversity Plug-In.
Have a look here:
https://www.amazon.com/clouddrive/share/UgHitXub1QkiNfbNqCvwjCAE1K7uxm7Oh553HA18V0Y
With the Object in your image above, you can bevel this line first, but then the I-Selection from the Boole is useless as the geometry is not the same anymore. (Except you bevel it before the Boole gets to work. See below!) A new selection needs to be created. I would go that path only if the way with Splines can’t be done, or what ever speaks against it, as the adjustments later on are way more difficult. The splines can be copied and replaced without jeopardizing the Bool set up. Certainly a time saver down the road.
I had so far no luck combining two Bevel Deformers while using the Angle Threshold for this specific set up.
So, going back several steps in the Boole, as I suggested in the chess analogy, I used finally three Bevel Deformer, to get this done, and keep it to a certain degree adjustable.
Scene file:
https://www.amazon.com/clouddrive/share/vXAlBJcdkS17lfVZFfHhYxcrsfk8mDo42rDzwppW7gI
Screen shot:
https://www.amazon.com/clouddrive/share/HiDSbochNupKWi4nIy9auNmtxmT9pO1ez2TQP8hiL5W
My best wishes
Edited May 20, 09.48pm PST