I usually shoot long exposures (20-30 seconds) between f/8 and f/11 at iso 100 with a wide zoom, I like to get as much possible stuff into the frame since I don't like empty space with one firework in the middle, the chaotic random fireworks we have here lend themselfs to this, since on their own they usually aren't that impressive, but you fill a frame with them and they get a lot more interesting.
GX-10 ISO 100
20s
f/9.5
27mm
vagrant10: That last shot of yours is I think one of my favorite fireworks shots ever.