Nigel's suggestion is excellent and I would vote for any push for the developers to incorporate this. We need a simple way to convert a Notes outline into child thoughts.
For what it's worth, my plain text editor EditPad (Pro) offers among its options "convert tabs to spaces" and "convert spaces to tabs". Other text editors probably do the same. Maybe you could incorporate this idea into your workflow, possibly as a text file attachment, and at the end of each session develop your outline from that.
At the risk of mentioning another application, TreePad allows one to insert separators within its notes along with a command to split the note into several notes, each under its own node. Conversely one can also merge notes with their nodes. This would be a good model for PB's developers to emulate.