This is both a mapping and scripting issue I suppose. I have never made a map before but what is the usual size of a skybox for maps like 'Ambush'? They usually dont have physical models outside of the play area so I imagine the actual map is cut off only a short ways beyond it. I assume that is where the skybox is,

I am doing some sight and bullet trace tests for a high altitude model and they do not work above 4500-5000. On that map at least. The model is clearly visible. Skyboxes do not perform depth tests for drawing of course however sight/bullet traces use masking so it wont pass through buildings and such. In effect the skybox is an inside wall. Is there a way to turn off the masking for the skybox via scripting? skybox.masking = false; or something like that?

not sure but i don't think so it might cause a leaking effect when compiling
good luck

There are no set sizes for the skybox. It is totally dependent upon the physical size and dimensions of the map. Everything must be contained within the skybox. Some mappers will place the skybox just outside of the reaches of the map while others will leave varying distances from the map proper to the skybox.

Messing with the skybox in any shape, form or manner would most likely and usually does create all sorts of errors.