Although I'm glad you like the build, GrahamO, it's only needed to play the Blue Planet mods. BP is designed to work with a special experimental build that uses cutting-edge features. The build I provided is a compatibility build for BP OS X players. For FS2 retail and all other FS2 mods, though, you should use the standard OS X builds, such as the official builds and the
nightly builds. Using a recent nightly build is recommended for now, because 3.6.16 has a difficulty bug that was fixed in nightly builds.
I can't help you much with the graphics, though. Although if you're still using the unofficial BP build, switch to the compatibility build. See
here.
EDIT: Clarification.