I searched but it is inconclusive. I found many numbers but no relation to the seating height.

I will try to explain.
I have a 26" TV right now it is at a comfortable height for my HT seats.
I am upgrading to a 54" which is literally over twice as tall.

I can't get the TV any lower as my center speaker is in the way. So, keeping the bottom of screen at the same height as the current SMALL TV would be alright then? I certainly don't want it any higher and have to tilt my neck backwards to look up.

because of the height increase of 2x, the top of the screen be 15" higher than now? and I sit about 8' away. Actualy screen area is 4x bigger :)

I think my eye is dead on with the center of the small TV now, but I have read if it's looking at the bottom 1/3 of the screen it is OK too.

Thanks... I am getting some help with the installation due to the weight, I want to get this right so I don't have to bother my helper again.

painters tape, mark out the wall where the TV would be and see if you like, if you do go for it or just move it around till you like it, much easier with painters tape than the actual TV itself

I have my 58" wall mounted so that the 1/3 point of the viewable area is at my seated eye level. If I were to place it at the mid-point the bottom of the display would be below the media center that is underneath.

If one uses a tilting mount then the set could probably be placed a little higher and then angled down a bit to accomplish the correct viewing angle.

Some people cut out Cardboard of the screen size and place that where they want to put the display and then see how it looks. Sit down and see how it is. You don't want to be having to look UP at the screen. Where after a couple hours watching a movie, you have neck pains for example.

On mine, when I sit on the Sofa, my Eye's are almost level with the Center of the screen, maybe just a bit lower then that. It's high enough that when I reline back and my legs are up in the air, I can still see the whole screen. I'm only about 6.5ft from the screen.

Some people put them above the fireplace. Generally that's a bad Idea as it's to high unless your back quite a ways, and maybe have it tilted down just a bit. Mine is mounted on a Swivel mount that's part of the HDTV stand. I have it up High enough to fit the center speaker right under it on the top shelf. It's better generally to have the center speaker under then on top. On top is usually just to high and your surround sound isn't as good. You want the sound coming at you and not over the top of your head.

painters tape, mark out the wall where the TV would be and see if you like, if you do go for it or just move it around till you like it, much easier with painters tape than the actual TV itself

+1

This is a good idea to test the height. The recommended height for a PDP is that the center of the screen should be eye level. Keep in mind where you would normally watch the set from if you have different height sofas, chairs etc. in the room