I’ve done several arrangements with some poetry involved with every movement of the music. I attached the text as system text to the beginning of each flow. I made the room for the text box by encreasing the heading bottom margin - which has been promised to reach beyond the current 35.27mm in the future, thank you for that!
So far so good. I quoted the poems using tab stops between verses. Everything fine.
Then I started seeing very odd behavior when looking at the text boxes in different layouts: the tab positions were not ok anymore and the font size of the text had been altered . After a considerable amount of frustration, bad language and the like I realized all this being due to the different rastral sizes I have in my layouts. The font size in the system text editor is NOT absolute as I thought it would be, but relative, hence reflecting changes in rastral size - and being system text, also spreading the change to other layouts.
I did my share of googling on anything that might help understand this situation and I did find the (or at least one viable) cure: using paragraph styles lets the user choose whether the font size is absolute or relative.
With absolute font size my formatting with tab stops is consistent throughout the layouts with different rastral sizes. Problem solved.
I’m writing all this to help others possibly facing the same problem.