I got idea ;) another little trick :D
Try my latest version and look at result. I reduce opacity of that light of moon over and under horizon and add additive "light" to back layer (same as moon) so result is when moon is under ground destination out light is not visible and when moon is at the sky this light has 100% opacity so moon is visible trough shadow and has red glow at back, not affecting other front layers, so it seems almost like whole light is really behind. So red glow is at back, light in shadow is at main layer but together it looks good. I cannot achieve that clouds will cover moon light but I think it is best result from all my tests. :D
PS: Maybe I can try to play with it more and when moon will be in collision with cloud moon light reduce opacity a little bit etc :D but I try to transfer this approach to my game and I will see.