Sorry to be harsh. Two facts prove, unequivocally, you are absolutely incompetent to perform the intended task:
You do not know the internal operation of a DPDT toggle switch, one of the most basic switches in the known universe.
You propose to eliminate integral crossover component and it never occurred to you to disclose to readers what position you employ the switch.
Stay away from soldering iron. Leave those speakers alone and enjoy them.
PS: I have two spare Focal fiberglass domes in superb condition for those, $100/pr + shipping. If you ever need one later, not likely easily found.