Hi,
Thanks again for your reply. I would like to apologize in advance if I am going to whine below, you are definitely not the right person to do that to… 
You may be right that it will be a learning process anyway, I hope that some things will go more smoothly in the long run.
Is there a way that I can send my file to you in a PM? I don’t really feel comfortable putting my files on a public forum where I have no control whatsoever over who has access to them. Very often I (and probably many of us) have signed an NDA, sharing something publicly is often not an option. Normally you would need a helpdesk for that, but unfortunately they don’t respond very quickly (or not at all).
Regarding the overcrowded pages, I had manually lowered the bottom system on those pages because, for example on page 31, the second system was through the first while the “inter-system-gap” is set to 13 spaces.
At the same time, there was still a large margin at the bottom of the page.
In the meantime, I have also experimented with quite a few different settings, but I rarely got the desired result. If this worked for one page, the other pages became worse.
I had similar problems with the settings for the placement of dynamics, hairpins, playing techniques… A setting that works in one place often does not work on the next page or even the next bar. In itself this does not have to be a problem (you also had to correct that manually in Finale for instance), the only pity is that manual adjustment is very cumbersome, because it seems to be against the Dorico philosophy.
Regarding small edits: I understand that Dorico has a certain workflow and that there is little point in continuing to think in the logic of Finale (I really try!).
However, even within one mode, manual adjustments are hopelessly cumbersome. For example, if you are going to do some layout in engrave mode, you want to move small items, fine-tune the spacing of the staves,… Within engrave mode, you also have to activate a different function for that each time. For example, if you are working on the spacing, you cannot drag Dynamics or playing techniques and vice versa. If you then want to add some small details in the notes or arcticulations during layout (which is very normal when proofreading), you have to go back to write mode each time. Opening two windows could possibly be a possibility, but that should be completely unnecessary!
When searching the forums, I also noticed that for many smaller problems there are often weird, complex solutions where you actually have to “trick” the software into NOT doing something that it would otherwise do automatically. Dorico makes a lot of assumptions and that is (sometimes) quite annoying.
A nice example was for instance the creation of a Sfzp dynamic. Something that is very commonly used and should actually be very simple. This is not included in the prefabricated options for double dynamics and consequently a whole workaround is needed to arrive at something comparable. It really should be easier.
I have to start working on the parts for this project after the weekend, hopefully that will go a bit smoother.
Again, thank you for your kind help and sorry for complaining but I just expected a lot more of it. The fact that the support team is also unable to provide adequate answers causes a lot of unnecessary frustration.
I was looking today if I could file a complaint with Steinberg for the lack of support. I came up with this:
That sums it up pretty well actually…