Just downloaded and tried Double Cut. 2 Big problems though;

1. It works great until you group the wall, then it reverts to single cut native mode.
2. Section fill (both Skalp and Native SI) does not work with Double Cut. i assume this is because the internal cut faces of the opening are grouped with the window (cutting object) not the wall (the object being cut.
   It would be a great pluggin that I'd definitely buy if they fixed these issues.