Since one of my design requirements is flexibility, the PCB provides some customization without having to make a new board. That said, you can certainly incorporate this into a project and eliminate it as a disparate component.

Secondary. The secondary can be isolated or tied to the primary ground. If an isolated secondary is desired R7 should be replaced with a 2.2nF MLCC reduce common mode noise.

Controller bias. The controller has an internal linear regulator that is necessary for startup. Beyond startup, it is best to power the controller via one of the outputs if they exceed ~ 9V. As TI points out, high input voltages almost necessitate the use of bias to eliminate the dissipation from the internal regulator. Use a 603 size jumper to connect the appropriate output, and keep in mind that if the secondary is used it must be tied to common ground via a jumper at R7.

Controller mounting. The controller has a thermal pad to improve heat dissipation. The PCB accommodates this and provides a generous copper pour. If you don't have a reflow oven or air pencil apply thermal paste instead. I used this method and the worst case rise was 50C.

Main inductor build. The board is setup to use a toroid core with an OD of 13.5mm. As discussed in the Theory of Operation section, core selection & winding configuration are crucial to minimize leakage inductance. Ignoring core losses, a core with the highest permeability that provides an adequate saturation margin minimizes the number of turns. A high turns ratio complicates the build. If possible use a bifilar winding (1:1 ratios). Otherwise an interleave is best.

For the inductor used in this project I used a simple interleave: winding 1/2 the secondary first, then the primary ('buck' winding), then the remaining secondary. Splitting the primary in half (so P/S/P/S) for four layers might get the leakage inductance a bit lower but it becomes difficult to do manually. The winding details are documented in the design workbook.

Wire size, type, skin effect, etc. is a discussion unto itself but since the currents are relatively small here it is more just a question of wire AWG to minimize DCR balanced with the available winding window. Ideally the secondary would use 28AWG vs. 30 but the increase in leakage inductance isn't worth it: this happens because of the increased air gap between adjacent strands. The window utilization also becomes very high (a machine wound core with 28AWG secondary wouldn't be possible), making the winding sloppy and further degradating regulation.

Installation. I intend to mount the unit as a daughter board using 20AWG wire with nylon spacers (hence, no mounting holes).