Does Quick Pitch produce a level perimeter?
If a level line is desired shim sticks with mud under the stick end to raise them up to a level line, then screed to the top of the sticks as normal.( Keep in mind that a shower where the drain is 4-6 inches from the wall as in the video, is an installation you would not want a level line as this would create a volcano effect at the drain. In this instance let Quick Pitch do the job as designed it will create the perfect slope as in the video.