Figured out a workflow:
Install these extensions:
1.
EpubPress - Read the web offline
2.
Save as eBook
Create an ePub file from several open tabs (1) or convert the current tab to ePub (2).
Save the ePub file to DropBox.
Use
FodlerSync to automatically sync your DropBox folder with the Articles folder (create one) in your Boox device.