'84 Spider Veloce
I have had the same problem. Never solved it to my satisfaction but never drive the Alfa in the rain.
please do keep us posted.I don't deliberately drive in the rain, either, but gojng to the AROC Palm Springs winter convention couple years ago we wound up driving in heavy rain for a couple hours. The top didn't leak and the wipers worked fine, which surprised me.
Rain can sneak up on anybody, anytime, and I need working wipers.
I ordered a set from ebay that might work, will post my results -