So basically, the duel has to be set up to trick the other guy into firing first (and missing)?

...I'd think the premeditation would take it out of SYG-territory, myself. If you intend to have a duel, and ostensibly your intent beforehand is to kill the other person (i.e. presuming you are not suicidal), then any attempt to argue self-defense would be pretty weak.

But at least it'll make some lawyers very rich.