Here I refined the shape even more.

I also worked on the bulge map again to bring the crease even lower.

I also extended the main map over the outer third of the collarbone to remove the dent that is caused by V3RR's default rigging, making it straighter.

Once you're happy, just click "FIGURE->Symmetrie->Right Arm to Left Arm" and the new weightmaps will be transferred over to the other side, too.

And don't forget to make BACKUPS between every step, so if you really mess up, you don't have to start over again.