Seems the battery drain is fixed for me now. I was trying a few things but am pretty sure it fixed right after I removed Gmail and Google Drive using Titanium Backup. Neither caused any wakelocks or alarms in BBS... Please note I have the newest Google Play Services for Play Music and that WiFi was on the whole time (which you can see in BBS log).
Screen light was on for around 2hours of reading at about 50% brightness giving around 12 days of stand-by with 35% battery left. I'm sure turning the frontlight down and using the frontlight less would yield around 20 days!