Tip 1 filters work wonders i think it make sence to draw it last but im a goof and i draw it early and use the filters to hide it.
Tip 2, well i dont have a tip 2 for ya cuz im not much of an LOD fan. But i would have to suggest that the sky box not overlap or touch anything in general.
mg42 probably overwritten by spearhead I see you have the addon menu item just use the one in there . Or change the mainta directory name to xmainta when you map for mohaa . You can do that to see if you get the mg back on your menu after you do that .
For your LOD, definately DO NOT use LOD to replace the bottom of your skybox. LOD is treated as detail by the engine, and will not seal your world from the void.
So be sure to have a structural skybox base, and build your LOD separately above it.