125vbuck-eagle.zip contains the Eagle board & schematic.  There are custom devices in the design but that shouldn't cause a problem you need to modify them.

Ideally 2oz copper should be used for the design but my builds have used 1oz without problems.  Advanced Circuits manufactured the boards in the photos.

This design uses three custom wound inductors:  current sense transformer, output filter, and flyback drive for the output SSR.  The cores for all three are in the BOM file along with notes on wire gauge and number of turns.

Be sure to wind / install with the correct polarity or the CT & flyback could develop high voltages that damage components.  A few pictures are included for guidance.

125vbuck-bom.xlsx contains the detailed component listing along with vendors.  Most can be ordered from Digikey.  They don't carry Magnetics MPP cores.  The core used in this design is popular and can usually be purchased on eBay.  I also couldn't purchase the controller from Digi and instead ordered direct from Microchip.

125vbuck-mplab.zip contains the source code.  This should compile as-is in a current version of MPLab & the XC8 compiler.  I do compile in Pro version but you shouldn't have any performance problems in Free mode since all timing critical tasks are handled in hardware.

The board design includes a USB micro-A/B jack to program the PIC using a PICkit3.  I did this to allow for easy updates through design iterations.  If you will use as-is and can program the chip before installing you can omit.  Otherwise you'll need to fabricate an adapter.

I designed the board to mount in a Polycase enclosure - the part # is included in the BOM.  File 125vbuck-case.pdf includes my chicken-scratch dimension mark-ups for the drill size & dimensions for the power switch & status LED.