Using different feet would not cause you any problems. I personally made a wedge shaped block to sit under that back of the speaker to tilt it down towards the listening area. In my case it did not really make much if any difference, none that I could detect anyway.. My personal feeling was that aimed towards the viewing area directly that I would get some benefit from the fact of being directly in line to the vocal point. In reality it did not make much if any difference in my room setting. Now having said all that don't forget that different rooms have different characteristics and maybe in your area by changing the angle of the speaker in your listening room you will find that it has altered some of the reflective energy maybe bouncing off a wall or the ceiling and will make more of a difference to your setup. You will have to experiment, you won’t harm anything and if you don’t like it then you can always put it back to how it was.
