Start from the last row, not the floor plan
The plan arrived with an eighty-six inch panel drawn on it and a note asking whether that was big enough. Nine metres long, five point six wide.We ignored the drawing and asked the only question that produces an answer: how far is the last row from the screen? Seven metres.
Everything else follows from that number, including the size, the seating and whether the room works at all.
Three to four times the image height, and what that means here
That range is where a 12-point font stays legible without the picture feeling like a cinema front row.A 75-inch 16:9 image is about 0.93 m high, putting the sweet spot at 2.8 to 3.7 m. An 86-inch is 1.07 m high, giving 3.2 to 4.3 m. A 98-inch is 1.22 m high, giving 3.7 to 4.9 m.
Seven metres is outside all three. At that distance an 86-inch panel is not a screen any more, it is a poster with a PowerPoint on it.
Why two panels do not solve it
The instinct is two 75-inch screens side by side. The join lands in the middle of the picture, any table spanning the width gets cut, and anything dragged across the centre disappears behind the bezel.Cheaper on the quote, worse every day for five years. I have not seen one installed that the client did not complain about by month three.
The change that actually worked
Move the screen to the wall nearest the presenter, pull the seating block back 1.2 m, and go to ninety-eight inch.The back row could read a table. The presenter lost half a metre of standing room at the side. That was the trade, accepted once the client saw the floor taped out.
If the room cannot be rearranged, keep the ninety-eight and drop four seats from the front row, pulling the primary sight line under five metres. It sounds like a compromise. It is cheaper than a screen nobody can read.
Three specs that matter more than the diagonal
Brightness around 350 to 400 nits: a 500 nit panel in a dim room is harsh and gets turned down anyway. Touch response under 30 ms: two people write at once at most, and palm rejection matters more than the point count.And front-facing HDMI and USB. If the ports are on the back, every meeting starts with someone crawling behind the screen and the cable gets left in.