Good, that's great to hear. There's one other thing that might help: HD6 (whose enbeffect.fx code you're using) in a way planted a mine in his code as there's a bit of code that will considerably increase night-time brightness. You can use search to find it:
Code:
float2 hndtweak = float2( 3.1 , 1.5 );
The first value is for night-time, the second for daytime. The 'right' value depends quite a lot on your palette, but perhaps first experiment with something like 2.0 for night-time and then adjust brightness and contrast accordingly with uctbrt1, uctbrt2 and uctcon.