I can agree with Flrnlamb. I should have said that it helps some if you use a bookshelf center; to try to stay within the same brand; hopefully one with the same or similar tweeter.
If you are using a center rear as well; you can use the same speaker and then not have to buy a pair and only use one.
I admit that I run separate systems, and do not get so fussy with the surround system which is just for TV/Movies. I can see you might have more difficulty if you want a perfect image. I still don't think a lot of center speakers are properly designed. Making it fit above the TV seems to matter more to some companies, rather than actually having it sound good.
If you are using a center rear as well; you can use the same speaker and then not have to buy a pair and only use one.
I admit that I run separate systems, and do not get so fussy with the surround system which is just for TV/Movies. I can see you might have more difficulty if you want a perfect image. I still don't think a lot of center speakers are properly designed. Making it fit above the TV seems to matter more to some companies, rather than actually having it sound good.