3 Questions I am awaiting to here the answer for: 

1. I have FS Global 2005 for FS2004. Yesterday I was thinking about the old bad stock scenery.
If I have FSGlobal installed and activated, can't I de-activate some scenery-layers from the scenery library?
I think this would make flight loading shorter and framerates a bit higher (ok, my FPS are high enough )

2. I also have Ultimate Traffic for FS2004 for almost a year. All the traffic is wonderful, but is there a way to make the engine contrails of the AI and my plane longer, so that after a while I have much nice stripes on the sky, just like in reality?

3. In which files are the scenery layers defined? I know I can edit them in FS or e.g. with SCM2004, but is there also a way to hand-edit, add and delete them? I ask this because of I create some scenery and want to it exported, it would be good if the installer auto-creates a layer.

Thanks for the info, but maybe I should have specified my questions further.
I was guessing that's what the scenery.cfg contains, but I don't know which tags mean what, e.g. what remote= and the others mean.
How can I edit those .fx files?
I of course know I can untick those layer boxes, but which ones? I don't want to make holes or disable buildings....