I am going to buy two screens more and run LFS with triple screen. My current display is a cheap 24" Samsung Syncmaster.

What would you suggest as side displays? Maybe even a pair of 19" is enough? Is there reasonable benefit to have same size (24") displays on the sides?

I would suggest you to do the same that I did in 2016.
So I had two monitors of the same model. They were 144hz and i wanted one more but the one's i had were out of production.

So i sold them both to a close friend of mine and bought 3 new one's. Same brand and model. I'm pretty sure the one's i bought back then are now out of production once again. But all i know is that they're ASUS 144hz monitors with low ms and i paid approx. €900.

I have had second thoughts about them, to instead have 1 big 32" ultrawide montior. That would've been cheaper.
Whatever you decide to do, you should have all in the same hz.

Quote from kristofferandersen :

Whatever you decide to do, you should have all in the same hz.

Thank you, this I did not think about

What I learned so far, things get too complicated if every monitor has different screen resolution. At least side monitors should have same resolution both.

Now I still have one problem: Otherwise everything is well, but for some reason when I activate triple screen with shift+f12 the whole system will have too much height and the bottom of the screen is cut. Meaning:

1)I will miss the OK/CANCEL/JOIN/whatever buttons in bottom
2)I can see only top names from connection list
3)etc... for example in F9 mode I cannot see my tyres

I don't know what I am doing wrong. Every screen is 1900 wide and every screen is running native resolution. I have Geforce GPU and same problem with 0.6T and U

edit: played with Nvidia settings and found "Configure Surround" -> Span displays with Surround. Now it works like it should! (still wondering why I can't spectate/freeview on triple screen like in other sims)

Quote from lucaf :

(still wondering why I can't spectate/freeview on triple screen like in other sims)

Options - View - Full width external views

The option is staring you in the face but you can't see it (same with everyone else by the way).

Quote from Scawen :

Options - View - Full width external views

The option is staring you in the face but you can't see it (same with everyone else by the way).

I was struggling quite bit to find this option. Found it eventually, i didn't know it existed.

shift+u to enter freeview. Press options bottom right and turn on Full width external views.

Sadly, I couldn't use LFS in triple-monitor-mode in freeview (shift+u) when i'm on live servers.

Avoid nVidia Surround if you can, it absolutely messes up with normal desktop operation

LFS's built in triple screen mode works better for me without surround.

Okay thank you! super! I have to say that the option is hidden quite well since you need to access the Options/View menu in Freeview mode (as kristoffer said), otherwise you will not see it.

Quote from kristofferandersen :

Sadly, I couldn't use LFS in triple-monitor-mode in freeview (shift+u) when i'm on live servers.

You almost scared me with this comment, fortunately it was not true for me.

Quote from lucaf :

Okay thank you! super! I have to say that the option is hidden quite well since you need to access the Options/View menu in Freeview mode (as kristoffer said), otherwise you will not see it.

It also works when you're spectating a car in TV camera mode.

Quote from Flame CZE :

It also works when you're spectating a car in TV camera mode.

Oh I see, you are right.

Another thing I discovered today, I am pretty sure the Bezel Compensation does not have any effect in Free View mode. That is of course not a big issue.

i am having trouble with triple screens, it assigns my left most as center! an di use Nvidia surround.
so i have to adjust the view to the right, and now i can not glance right to look but i can center the view.
how do i correct this?

Options - View - Multiple screen layout.

Set to 1 left and 1 right screen.

Usually it would default to this 3-screen setup, depending on the screen resolution. What is your total screen resolution?