Only have an idea on some of your questions, but here goes:
- For horizon merging, may be better to do it to the texture files outside of 3Dsimed, so in a normal graphics editor - is doable and might be easier.
- For texture merging, same thing: find some ready-made ones or merge 'em yourself in a gfx editor.
- There's a program for making track layouts on rfc?
http://www.racedepartment.com/bobs-track-builder/37470-creating-track-layout-pic.html
- I think you can change the sun's position in BTB yourself (not sure, never bothered with it myself )
- For horizon merging, may be better to do it to the texture files outside of 3Dsimed, so in a normal graphics editor - is doable and might be easier.
- For texture merging, same thing: find some ready-made ones or merge 'em yourself in a gfx editor.
- There's a program for making track layouts on rfc?
http://www.racedepartment.com/bobs-track-builder/37470-creating-track-layout-pic.html
- I think you can change the sun's position in BTB yourself (not sure, never bothered with it myself )