Questions regarding a custom Timeline playable implementation.

Use Case


Manipulate a Transform, then when the clip has passed, the Transform should retain the manipulation.
Call them 'Additive Clips' if you will.

At times I wanted to post a question here, but writing out a post cleared my thoughts every time.
The result though, was a rather thorough writeup of my progress, and the resulting prototype.

We are now giving it a spin, and if all is well, we want to use it in production of our next project.
It would be nice to have some feedback on the current implementation, since I don't want to run into trouble down the line.

You can read the post here: https://dreezn.blogspot.be/2018/01/prototyping-custom-clips-in-unity.html

The Questions

• The obvious one: Did I use the correct approach in getting clip start/end times in the mixer, or is there a 'supported' way of having these cumulative transformations work using custom Timeline Playables?
  I feel like I'm jumping through hoops to get this use case to work.
  
  
• As mentioned in previous forum posts, funneling values from the mixer through to behaviour is a workaround, and feels like misuse of the Playable API's architecture.
  What are the implications of working with this solution, and more importantly, is this advisable in a production setting?
  
  
• It would be nice to have more context about the CustomTransformationTrack.GatherProperties' override, adding Editor code as present in some of the Default Playable package's examples, but not in all of them. The Default Playable's wizard did not create this code for me, so I gather it's not needed. Still I'd love to have some insight in whether or not I should include it in my use case, and why.
  
  
• Setting default values of custom timeline clips.
  As I mention in my blog post, it appears that new clips now get a length of 300.
  It would be nice to set this somewhere.
  
  
• The meat of a clip's template contents we extracted in a ScriptableObject, that way, instead of setting each template manually by hand for each clip, we can simply reference an asset there, this asset can then be re-used across multiple clips, making the workflow much faster and modular.
  Would it be possible to handle dropping such an asset directly on a track, as this is supported with AudioClips?
  (I have noticed however, that dropping an AudioClip on an existing audio track always creates a new track. I'd expect it to add a clip to the existing track instead)