I have used both silver and rosin solder and i think they both work,i havent heard of using a torch to smooth the joints but i would imagine it might work. You can get the same effect as a torch on a ugly solder joint if you just move the solder iron on the brass about a inch from the joint and heat the brass,then the heat will cause the solder in the joint to "melt". Right at the point that the solder starts to turn to liquid pull the iron off the brass and the solder will cool in a smoother puddle.

Also.....

If you lightly sand the ends of the brass with some steel wool it will also help to get a better joint in both apperance and strength[8D]