I am sure there are some meshes that overlap each other (eg north america and then there is the rockies mesh). Can you install the rockies over top of the north america mesh? or can u install a 36m mesh over a 76 mesh? thx

Yes, and yes. The sim will use the highest LOD it finds. Keep in mind that the higher the LOD the shorter the visual range, and vice versa, so by installing multiple LODs you are creating concentric circles with more detail closer to your aircraft while improving the intermediate and longer range terrain detail over the default.-------Justinhttp://www.fsgenesis.netHigh Quality Scenery for FS200x