Not sure I completely understand your issue. Are you referencing the sharp edge along the top of console opening and the vertical wall down to the switch assembly? Was wondering if you would be able to raise the switch assembly enough to have it actually protrude a bit from the opening, or possibly be flush with the opening's top edge (e.g., window switches). Then painting the console opening & sharp edge would not be as significant an issue. But if you couldn't do this, then my experience with painting the vertical edge is it has to be done using application of light coats of spray paint to both avoid any runs and get good adhesion. 3-4 coats should suffice; possibly with a surface adhesion coat for plastic material. And another possibility is to spray the vertical wall with a black paint (gloss or flat; your choice) to add some focus to the relocated switch assembly. Just requires more masking.