Now I'm adding to the confusion. I am NOT interested in using Kerdiboard or Wedi at this time.
Is there a way to compare the durability of the waterproofing systems from Kerdi, Nobel, Laticrete, Mapei and Ardex? For example, how do the sheet waterproofing membranes from Kerdi and Noble compare to the liquid applied systems from Laticrete, Mapei and Ardex?
As you say, the hardest part is the connection of the tub to the backer board. The Kerdi installation instructions show Kerdi-Band bridging the backer board to the tub. Thin set was troweled on to the backerboard and a bead of Kerdi-Fix on the tub flange. Then the Kerdi-Band was pressed into both of them. Your first picture in post #3 looks exactly like that. Your picture in post #5 shows another example with Hydro Ban liquid coating on the backer board and Kerdi-Fix at the tub flange. In this case did you fill the gap between the backer board and tub using Kerdi-Fix only? There doesn't appear to be a sheet membrane between the tub and backer board. I'm assuming the Kerdi-Fix is the dark grey material in the picture.
Thanks for your help. This is very informative.