OP - As everyone (except a numpty saying it's too big as you can't see all the screen at once!! How far are you watching at - 3 feet?!) has said to you, go as big as you can. You will get used to a 65" in minutes. Get a 55" and within those same minutes you'll be saying - I should have gone with the 65. GO BIG!
I use a 65" LG G4 between my Maggie 1.7i's in a 22' x 16' room, with speakers 'fireing' down the long length. There's c2' from Mag outer panel edge to the side wall, and a bit less between the inner panel edge and the TV, on the same plane. Eye to panel is c12'. The TV in the centre though, DOES affect the stereo image - the TV is on a stand and is c3' from the back (you lot, in the US, weirdly, call it the front - how can a space BEHIND the speakers be called the front?!) wall. For 'critical' listening I put a thick/heavy soft blanket, doubled up, over the TV screen, and the image has a better focus - singers/instruments are more sharply defined within the excellent sound stage the Maggies produce.
Anyone who says you don't 'need' a centre speaker, is,,, not correct! It's an ABSOLUTE necessesity. Messing up the sound stage of a film without a centre is a heresy. >60% of the mastered sound comes from the centre channel. It's there for a reason, and the reason is easily heard when doing an A/B comparison.
I took my centre speaker over to two friends' who also believed a centre was not necessary, and after trying a few films with/without, they both bought a centre speaker and said it (watching a film), was a MUCH more involving experience with a more even soundstage where vocals were much better produced, and the whole film sound stage was more clearlly defined. And, as for the poster who doesn't use a pair or rears!!! Wake up man, you're missing a MASSIVE amount of film experience.