What is the correct left defroster duct size for a non a/c 1974 Duster?

The both dash defroster vents are 2 1/2. The one hose tapers down to 2 1/4. Hard to save the old brittle paper hoses if you don't know how to release the clip. Been saving them for a long time so when I build car I would have them.

I have seen repops for sale but not sure where.

The AC hoses are very pliable and have built on clamps you can unclip. I never tried an AC style on a non AC car . Always wanted to but never needed to.