Regarding the invocation.
"'In the name of the Father and of the Son and the Holy Spirit'. This is the guiding sign and measuring stick (?) (Vorzeichen und Massstab). God himself meets us in the divine service, in human words and signs. What we experience, hear and see, directs us beyond the visible. The divine service directs us to watch everywhere for signs of the presence of God."
Is this all true, but too vague again? And what is "Vorzeichen und Massstab" supposed to mean? It does not really say anything.
In our hymnal it says that "all may make the sign of the cross in remembrance of their baptism."
There was a time, where making the sign of the cross is "too catholic" to do. I, myself, have to say, I have not been able to get myself to do it often in public, though I will do it in private prayer. It is good to have this teaching to go with the practice: in remembrance of baptism, which is that it was God himself who made a beginning with you, who saved you even there. Not something bland or non-descript, not just a "sign" either. But the actual doing with the word together. It has been done. You have been baptized. If you can't believe much else at certain points in life, this will always hold and you can always go back to it. God has made his beginning with you and made you his child.
In the service, too, we remember that it is God who has made a beginning with us and assures again and again. And we are in the company of the fellow-baptized, a whole community.
I think that is more succinct and comforting.