Ok chaps - here it is, instant fps boost by changing some settings in the lock-on/config/graphics.cfg file
open the graphics cfg file,
scroll down to LandLodDistances,
edit the LandDay values TO,
L01 = 8000;
L12 = 15000;
these are the same values as LandNight,
you can also try changing the MFD a bit further down in the same list.
Play around wityh the values above I;m currently set at 9000/20000
LOMAC runs like a dream, 50+ f/ps forward cockpit view in clouds !
This is serously the best tweak yet.