Is there a way to tweak the flashlight beam?

I’ve been integrating in my personal gamemode “flashlight as a distinct weapon” so that players can either hold a gun or see where they are going, but not both.

But the flashlight beam you see coming from your teammate is quite deceiving, i know that the flashlight you see in first person is only visible on your screen, but is there some way to “improve” the flashlight beam on your teammate?

I think you’d have to remake the flashlight yourself for that.

That’s the thing, i don’t know if the flashlight can be modified at all…

The flashlight is able to be disabled or enabled in lua but thats about it as far as I know. You might be able to interface with it using the render or draw library.
The flashlight itself is a projected texture similar to the slide projector in cs_office. If you edit the texture, you can easily change the beam width and colour. Theres loads of custom flashlights on FPSBanana in the Sprites section.

You have to create your own custom flashlight.
Take a look at http://www.garrysmod.org/downloads/?a=view&id=81163

The guy has edited it, so just look at how he did it.

He did it. Like this:

You need to disable the flashlight normally and handle it yourself. Look into the L4D flashlight script to see an example.