Thomas, there are two hidden options which might help you here:

• MIBRevealingApplication: after extracting files, use this application to reveal them. Try this one first.
• MIBViewingApplication: if no default application is defined for a file type, this application will be called to handle it instead.

To set any of these options, open Terminal.app and enter these commands, each followed by pressing Enter:

• defaults write com.macitbetter.betterzip MIBViewingApplication "PathFinder"
• defaults write com.macitbetter.betterzip MIBRevealingApplication "PathFinder"

To return to the original state enter these commands:

• defaults delete com.macitbetter.betterzip MIBViewingApplication
• defaults delete com.macitbetter.betterzip MIBRevealingApplication