Command argument from snapctl get

I feel that some kind of “best” practice is needed here since this must be an extremely common task:

  1. Design a custom unit-file.
  2. Populate the start parameters based on the snap config.

I have previously created mods like this: How to customize systemd service created by snapd?

But I don’t know or feel this should be the way to do this from within a snapcraft.yaml context.

I really can’t find any good docs on this method.