28 to 34-tooth front derailleur spacer

I wanted to mount a SRAM Rival front derailleur on my vintage frame with a 28mm seatpost. The derailleur has a clamp for 34.9mm tubes so i designed a spacer. The spacer needs to be stretched with force to get on the tube. I also recommend to tighten the screw more than the recommended 5Nm. I have not tested the mount under load yet, so use this with caution.