Thank you for your answer. I dare not customize my 505.
I added your proposal as an extra.css rule.
No change. If I consider a full page of text, I still have on average 25 lines, which I consider to be too much and which also provokes some artefacts.
I would be happy with 21 lines.
I will check my stylesheet.css for line-height.
and then used again my surgical little utility to change every occurence of
line-height: 100% to
line-height: 120%. This time it did not work and caused a terrible jumble of text which made the file unusable. So I am still stuck with this problem.
So, due to pending problems, I still follow on publishing in PDF and ODT formats.