If you rename the fsx.exe file of the 2nd installation to fsx_2.exe or some other name and
when that version is first run it will create a "fsx_2.cfg" file so you will have separate
CFG files for the two versions. I do this and it works well. I have 4 or 5 uniquely
named fsx_xxx.exe files and cfg's.
As for scenery cfg files, there are a couple of ways to deal with this. You can create different
scenery.cfg files and keep them in "adjacent" folders to the actual scenery.cfg file location and
then just copy the version you want to use at a given time into the normal scenery.cfg file location.
I have several scenery.cfg files created for different areas/types of flying. I have "default only"
cfg, "Europe", "USA", "Hawaii" and "OZ" scenery.cfg files. You can add a comment at the top
of each cfg file //USA Scenery or //Default Scenery so you can keep track of which one you
are currently using.
Another approach is a bit more exotic and entails mounting a drive in an empty folder. I use this
approach to share my "Addon Scenery", located exclusively on my J: drive, between my dual-boot
Xp Pro FSX install and my Win7 x64 FSX install.
In my case I mount the J: drive in the empty "Addon Scenery" folders in each of the two installs.
One could mount two different drives that had only addon scenery to the two empty addon scenery
folders but you would still need to have twoo different scenrey.cfg files that you would swap as
discussed above.
The saved flights and flightplans would be shared between both versions but that shouldn't
present a problem. The gain is in having eunique fsx_xx.cfg files where you have unique
"Main" sections then may or may not enable other SimObject folders.
I keep my AI, Military AI, Propliners, Military Aircraft and Aircraft (ala FS9 ) in separate
folders so that I can enable/disable those categories depending on how I want to fly.
Paul