Caveat: Please keep in mind that I am quite the novice when it comes to making reeds, so try this at your own risk.
I recently made two reeds for my Hillmann chanter which worked great, but played consistently at a higher pitch (it was as if my D chanter was an E chanter – it sounded in tune with itself, but was one step higher than concert pitch).
Because of “architectural constraints” I couldn’t reseat the reeds higher on their staples and was hesitant to move them to other staples because the blades of the reeds were quite “happy” sitting where they were. Since I have other working reeds I thought I’d use this as an experiment so here’s what I did:
I took a conical metal punch and hammered it into the end of a copper tube the same size of the staple. Then I cut off this end of the tubing so that its length was about a quarter of an inch. Then I seated the staple of the problem reed into this extention and sealed it with a heat-shrinking insulator for wires. I then refit the extended staple into the reed seat and after a few minor adjustments with hemp I got both reeds to play in tune in D.