@Electroman please note my diagram carefully - you need to also make changes at the 3-gang box for the HS210 connection 

@Electroman OK, sounds like progress! 

You mean you want to change out the toggle switch for a paddle (Decora) style, similar to the Kasa style?

Any brand 3-way switch will work - just ensure it is 3-way and not a std switch 

You can find at HD/Lowes or order from Amazon - just search on 3-way switch 

@Electroman 

Compare this diagram from my Tutorial 

And this is what you should have ended up with 

Electrically it is identical - it just uses different colour configuration for the Traveler Romex and the fact that in your case both the Line and Load are actually present in the same box (the 3-gang box in your case) 

But hopefully you can see that it is in fact ultimately electrically the same 

Incidentally tip on attaching images - if you click on the image icon (between the bullets and table tools) tool on the toolbar, you can upload your image using that and then the image will be embedded directly in the post (like mine here) rather than having to make the reader download it in order to view.