Saw that one, Unfortunately he's saving the actual image design aspect for another tutorial. I'm using his template to get the sizing correct.
Does affinity have an option to merge only visible layers? Like an auto mode? I'm using inkscape and I think I would have to go through and select every single overlapping path. There are 100's in this vector...On the tayda UV printing page they make a point of not having colors overlap and show you what to do. Probably have to clean up the overlap and merge them or subtract like I had to in affinity.