but I really think you are putting too much into this step.
I totally agree with your thinking, but in a real world, you have too many variables to consider.
I would silicon caulk the wall intersection, and I would silicon caulk the tub and wall intersection. Corners whereever they are are the areas that will weep or seep water quicker. So, that is where silicon goes. I would load up those intersections and then with a wet finger in alcohol, smooth or make concave the caulk line. Then bring down that finger mark through the tubwall caulk to act as a water down spout. Your caulking on the tub wall should be a ramp to take the water off the walls and smoothly ramp off the tub wall intersection on to the tub. Remember, the silicon caulking job will be a observational maintenance job to ensure that its properly covered with any movement. Tub wall movement should be negligent if any, wall wall movement will vary with seasons.
Use a good Silicon caulk like a 35 year GE caulk. Make nice smooth ramps and concave drainage alleys.