We have sourced a crimp-on 1/4" quick disconnect terminal for 22-18 gage wire that is functionally equivalent to the quick disconnects used on the original Volkswagen wiring harness.  Don't use an ugly hardware store crimp terminal again!  Our terminals fit all 1/4" OE wiring connections.  They are a silver color rather than the original bronze/copper color.  These are sold in packs of 10. 
 
We recommend a ratcheting-style crimping tool to install these connectors.