https://github.com/unixdj/depcb

Graphical assisted editor for creating PCB's from images

Conformal coatings can make PCBs difficult to probe. I've had good luck sonicating in IPA for 15 minutes. According to http://www.empf.org/empfasis/oct03/3403rcc.htm this it means I likely have only encountered lacquer. Maybe other coatings are less common though so likely won't be an issue for others either.