Yes, 56% silver is much easier to use when brazing water bottle bosses. Fillet Pro is kind of gummy when melted so it has built up qualities that will act more like melted brass (actually bronze but frame builders call it brass anyway) and collect and stay put on a the joint. It is best used for fillet brazing together light heat treated tubing.when not using lugs. If you are going to use lugs, then you need to get 56% silver. If you are going to put a frame together by fillet brazing, then it is much cheaper to use brass for practicing. Both Cycle Design has bronze rod and various frame material suppliers have Gasflux C-04 bronze rod. You use that in combination with their Type B flux (don't use silver flux). One of the principles of good teaching is to provide a student with the right materials that give them the greatest chance of success. The goal is to shorten the learning curve so they don't get discouraged and quit.

In your video you took extra time to try and get your Fillet Pro to flow out around the boss. That extra time led to burning off what little flux you had on the joint and scorching the tubing too. It didn't help that your flame pattern was too large of a circle. Your flame should have just been circling around the edge of the boss and a bit on the tubing. If you had used 56% silver with the right flame intensity and pattern, the silver would have like magic flowed around your boss and you would have cleared out of there long before your tube got red.