I have an old 46 inch set that I want to replace with an hdtv. Trying to decide if 50 inch widescreen will look too small. Can someone give me the actual dimensions of a 50 and 55 inch screen. I want to cut out a piece of cardboard to see what it looks like for 12 feet. Btw...I am leaning towards the sony 50a10 but the 55a20 looks so much bigger .