Delete if not allowed, as it's sharktank related, but I thought it might be helpful for builders.
On my latest design I figured out a solution to the board mounted/square hole thing - correct me if someone already cracked this nut..
If you make two sided PCBs, it's pretty straight forward to put a positive and negative pad on opposite faces of an edge. It doesn't matter which. In this case I needed to clear between two board mounted jacks, and it was a tight fit.
The base of the DC jack (between the pins) sits right up against the edge. The cutaway only has to be the width of the threaded part, and however deep your design requires.
The result, although difficult to drill holes for, is very tidy