since the top of the soffit is open, can you not fish the wires up through the soffit so it looks more clean. I may have missed something there.. Were you have them now looks good. If I remember correctly what danny said was the way he designed it, 16 inches or so. You may not get perfection, but it will still sound great. don't sweat the small stuff, i know, even if you are the only one who knows .... you still know and it will bug you. ..
JP