It's about the same between tin and silver, the major change is temperature
. Your brazing torch seems good, it's like some Maxigas torchs here in France. It's ok to braze tubes, but not really for massive parts because it's not as powerful as a true torch. Flux is normally incorporated into silver rods, but you can use a special one to help a lot in some cases. It's written on the box anyway, each brazing/solder has its flux.
Silver rods are 6 or 40 % generally, you're right. At 40%, it's easier to use (lower fusion T°), but higher price... The other 60% is copper, so more copper into rod = higher T° to melt it = difficult work. You could use copper/phospore, despite it seems more difficult to use (higher T° ~800° !) but I believe it's cheaper, not sure. Here, people prefer 40% rods generally.
You should practice with 2 tubes in order to have an idea of the needed temperature and how to apply rod to make a good joint. If you know tin soldering, you won't have too much problem to make a proper silver brazing