I haven't tried either Gasflux or Cycle Designs stuff. Maybe I don't know what I'm missing but I get along very well using what I am. I'm getting Petersons flux (No1 Blue) and off the shelf bronze from the LWS. Can't relate to the torch and tip sizes. I currently use a Smith medium duty (CW5A). The tip sizes are different from the light duty shown in the chart. I'm using an MW201 and MW205, which I believe relate to AW205 and 207 respectively.

With the "blue" flux I use it both powdered and paste. Throw a little powder in a jar- add a little water- screw the lid on tight and in the morning you have paste.

One factor that contributes to my success (I believe) is cleaning the rod. I sand all the coating off and pull it through an acetone rag. Nice clean fillets with no pinholes. The flux comes off in "very" hot water. Very little cleanup. I don't know the brand of filler, but it probably helps that the LWS supplies a big share of framebuilders here in PDX, and they are very knowledgeable and helpful.