I'm planning to update my setup this year by buying 3 large TVs to provide full wrap-around visuals, i.e. one in front, and then two at either side, almost at right angles to create a sort of box

I think the size needs to be driven by a couple of things;

 - TVs need to be big enough to enable me to sit inside the "box"

 - TVs need to be big enough so that when I look left and right, I'm not looking at the edge of the TV, but that the TV goes slightly back past my visual range

anyone created such a setup and have some suggestions?

I have a 55 inch single TV currently for simming, and it's not big enough for such a setup - I also have a 75" TV in the living room which is too big, so I think the sweet spot will be 65 inch - would be interested to hear of anyone else's approach/experience

The size of the screens mostly on the distance from your eyes. If you move the screens closer to you, you probably don't need 65" TV's.

Is there a reason why you don't contemplate using VR? A full wraparound image without any edges or transitions using TV's won't be perfect and you will need a lot of GPU power to drive three 4K screens in decent quality.

4 hours ago, EGLD said:

I'm planning to update my setup this year by buying 3 large TVs to provide full wrap-around visuals, i.e. one in front, and then two at either side, almost at right angles to create a sort of box

There are a number of very informative videos on Youtube about setting up multiple views. Also a number of videos of existing home setups with different side angles, mainly showing screens in the 55 inch plus range. I would recommend a search because seeing them in use is far more useful than written descriptions.

Regarding the side angles, I personally think it gives a better effect with the side screens in the range of 45 to 60 degrees rather than at 90 degrees. The latter puts the side screens very close to your head, and gives a very oblique view which does not work well with flat screen tvs. You can try it with your existing screen.  I would suggest hanging dark curtains, cinema style, to mask the side areas beyond the rear edges of the side screens. Then, in use, you will only notice the screen images.

I've currently got 3 x 48" LG OLEDs. Prior to that I had 3 x 50" LEDs. Personally, I wouldn't go higher than 50" but I know plenty of people do. Its a matter of preference and available space given how you need to sit. If you haven't seen it, I'd highly recommend watching Russ Barlows video on the subject here - Its a few years old but still applies;

 

Then, use this (or one of the websites Russ mentions) to work out your dimensions etc etc https://www.desmos.com/calculator/8ud3eka8kc

Be cautious about making it "a box" - I initially tried that before finding the above videos/sites - I found it difficult to setup, particularly with MSFS limited multi monitor setup. P3D is more capable in this area.