@tedster: thanks for the comment of MC which sounds quite reasonable
@g1smd & lucy24: the source website is a very large one, still in operation, the new website was earlier implemented as a directory, nobody feels fully responsible, therefore this website is in a chaotic status, a mixture of www and non-www urls, sometimes canonicalized, a lot of 404s, special CMS....
I only know definitively that they will use 302 redirects because of their strange understanding of "302 = temporary move" (I hope they will not mix the target url format!).
Therefore I have the choice between pest and cholera.
I would prefer the choice of the one additional redirect because DC seems to me to have more disadvantages. What do you think?