In my first response I suggested utilising Shortcuts as a conduit. Shortcuts has a URL scheme and also tight integration with Drafts via the Drafts actions Greg developed; specifically the aforementioned “Update Draft” action. 1Writer also references some level of Shortcuts integration on it’s web site home page, so URL schemes may not even be required at all depending upon how you would wish to trigger it.
If you are particularly set on or simply most comfortable with utilising a pure direct URL scheme solution, then the
replaceRange parameter could certainly be utilised. For replacing all, you would always want to replace from 0, so the first range parameter is easy. The end of the draft you could set as something arbitrarily high to always catch the end (e.g.
Above I’ve covered the all content situation. Dealing with subsets comes back to the point in my second response where I queried if this was in fact your intent.
That would still require some sort of marker or set of unique delimiters you could replace against or you would need to keep a separate store accessible to 1Writer that could track the original range. Note that if you use a range rather than a marker or delimiter, you are practically restricted to only having one artifact to work on at any time for a particular draft as when a replacement takes place this could affect the position of other artifacts, and unless you were also going to recalculate and refresh the stored data each time, it has the potential for data loss and corruption of the content.
If you are going to deal with transitioning sections from within a single draft then you have to consider what your preferred approach is and there would be a more involved solution involving some level of tracking within the drafts.
Hopefully that all makes sense and gives you some options on ways to proceed.