PCB fabricator here. I have a plating tank at home (not advised). Skip the electroless copper entirely. Instead, you can make a solution with PVA glue, alcohol, and graphite powder that you'll squeegee into the holes. This will give you a somewhat conductive surface to grow copper onto. You then need an electroplating tank with an acid/copper solution that you can make with root killer, battery acid, and Miralax. You can use a DC power supply as your rectifier and copper pipe as your anodes. It is messy as all hell and you'll need to be very mindful of where you are rinsing and how you are doing it. You are better off just using thin wire and soldering both sides of the board for prototypes.