...which wire or welding rod should I use to make a weld that will
be visible and aesthetics.
Assuming you want the weld to be invisible (not "visible"), I can
recommend using hammered pieces of something like Lincoln bare 1/16"
Low Fuming Bronze welding rods. Test to make sure the rods melt at a
temperature lower than your jewelry brass. Red brass is OK, in this
regard, but 80-20 brasses will melt before the rod does. Use the
black flux with the welding rod.
If this doesn't work for you, Rio Grande and Metalliferous sell
sheet solder intended for use with brass.
Brass is fun! Enjoy!