Well, it is more difficult here than when translating a book because here you have to consider the actors' mouths movements and other factors. 
There is another principle: "so treu wie möglich, so frei wie nötig." (as close to the original as possible, as free as necessary).

I think I would try to keep as close as possible to the English script. Why not have John starting the dialogue by saying: "So, der beste Mann." If you keep this expression you can better translate the "bester Mann - bester Freund" thing later on and keep Billy Kincaid and Greg in the game as well.

Of course you would have mention "Trauzeuge" somewhere, like in "der beste Mann - für die Hochzeit/als Trauzeuge/für diesen Job". If it does not fit with John's mouth movements you could have him say this as voice-over while the camera is on Sherlock. Please note that I have no idea of dubbing but this is how I imagine you pull this off. 

If there is time I can have a look at the dialogue but for now there is breakfast. Without eyeballs. 
 

Gosh, I wouldn't even want to warrant a guess how they're gonna do it, because John's "What do you think?" is kinda in the way. They'll have to do some serious creative dialoguing on this one in the German version. Here's the dialogue that I pulled from the LiveJournal transcript.

JOHN (sitting down): So. The big question.
SHERLOCK (turning to face him): Mm-hm.
JOHN (folding his hands and putting them onto the table in front of him): The best man.
SHERLOCK: The best man?
JOHN: What do you think?
SHERLOCK (instantly): Billy Kincaid.
JOHN: Sorry, what?
SHERLOCK (quick-fire): Billy Kincaid, the Camden Garrotter. Best man I ever knew. Vast contributions to charity, never disclosed.
(John frowns.)
SHERLOCK (quick-fire): Personally managed to save three hospitals from closure and ran the best and safest children’s homes in north England.
(John tiredly rubs his fingers over his eyes.)
SHERLOCK (grimacing briefly): Yes, every now and again there’d be some garrottings, but stacking up the lives saved against the garrottings, on balance I’d say ...
JOHN (interrupting): For my wedding! For me. I need a best man.
SHERLOCK: Oh, right.
JOHN: Maybe not a garrotter.
SHERLOCK: Gavin?
JOHN: Who?
SHERLOCK: Gavin Lestrade? He’s a man, and good at it.
JOHN: It’s Greg. And he’s not my best friend.
SHERLOCK: Oh, Mike Stamford, I see. Well, he’s nice, um, though I’m not sure how well he’d cope with all ...
JOHN (interrupting): No, Mike’s great, but he’s not my best friend.
(Sherlock looks at him thoughtfully as if he can’t think of another friend to suggest.)
JOHN: Look, Sherlock, this is the biggest and most important day of my life.
SHERLOCK (dubiously, pulling a face): Well ...
JOHN: No, it is! It is, and I want to be up there with the two people that I love and care about most in the world.
SHERLOCK: Yes.
(John nods. Clearly oblivious, Sherlock waits for him to tell him who these people are.)
JOHN: Mary Morstan ...
SHERLOCK: Yes.
JOHN (sighing tightly): ... and ...
(He looks up at Sherlock, who is still waiting patiently for further information. Eventually John pulls in a long breath.)
JOHN: ... you.
(Sherlock blinks rapidly several times but otherwise doesn’t move or react.

It shouldn't be too difficult to translate "you rub people the wrong way" into something similar in German, though. Could be something simple like, "Sie gehen Leuten auf die Nerven" or something with "anecken" or so. The truly tricky parts are when there's puns or play on words involved...

Last edited by TeeJay (March 1, 2014 3:08 pm)

Yes, that works too, I guess. I think it'll largely depend on the context of the rest of the German dialogue in that scene, but they should be able to make that work. Hehe, now look, you're almost making me want to watch the German episodes in June, just out of curiosity how they translated all the Sherlock & John banter.

"Du stößt sie vor den Kopf."