Hi @Nikolai_Myklebust, I didn’t look at your project, but I recreated one, following your description. Here the result, which I think suits your needs. And with no page overrides. Please, study it (to see what the possibilities are), and if you have questions, please ask:
Dorico file result:
layout with concept-ideas-piano sketch-score.dorico (581.5 KB)
Here some screenshots of some of the things I did:
Here two example of the score FIRST page template music frame assignations as an example:
I also assigned the instruments to the flows strategically in Setup mode.
For clarity I deleted all the Instruments Parts Layouts.
The Layout where I made all this changes is the one called Full Score customised.
Closing thoughts
Nevertheless: that done and said, I am not sure that this is the best approach.
My suggestion, instead:
You could just use several different layouts for your concept, ideas (that one in one layout maybe), and sketches, and then use another Layout for your score. You can very easily switch between various layouts, and don’t need to move the page template changes in Engraving options (using the little arrow icon in the upper right Pages panel) in case your sketch needs to be longer that expected for example. Using different layouts would be the way to go (and all still remains in one Project).