LOD Modeling numbers? Any recommendations...

for say a terminal? I'd like to try LOD modeling for my CYYG terminal but have a couple questions first. I noticed that there is little difference in frame rates whether I'm all the way out and all airport objects are in view or I'm smack dab in front of the terminal with only the terminal in view. Maybe LODs are not appropriate for this airport.Secondly, I tried making some LOD models, about 7 different variants of a sphere ranging from very complex (Sphere_LOD_700) down to a very simple shpere (Sphere_LOD_10) - all with radius 20m. What I was seeing was more than one model displaying at a time. I'm guessing this has to do with the fact that I probably didn't pick appropriate numbers....This leads me to my question... what would be appropriate LODs for say a small terminal and maybe something like a jetway. I was thinking I'd do a max of say 6 model variants.Thanks in advance,Adam