I have seen other riders solve these clearance problems by cutting the fender at the tight clearance point & attaching each piece with zip ties. I have a Bianchi Trofeo that has the same stay attachments with very little clearance at the seatstay bridge & while i was just able to get the necessary clearance, I'm thinking of splitting the rear fender so it can better follow the wheel curve & leave maximum clearance at the bridge. Don