Hi there!
Just a few words regarding: the volumen of the video made by the VBR 2 pass coding sometimes is significantly less then made by CBR coding. I don't know why... Comparing with the classical H264 system coder, is less, too. For example: CBR final result - 96 Mb, VBR 2 pass - 67 Mb. The same initial video!
Logs will be provided later.