You don't have to follow the guidelines to the letter, they are just a suggestion, but your current choices aren't going to work. Corner/ceiling is a bad spot Speakers should be roughly ear level when seated, but you can mount them higher than that. Use wire tracks or flat wire to hide the wiring or stand or wall mount them and run the wires from wall plates from below. If you are going to go up top, just go with in ceiling surrounds.