Find center of 2 curves

 From:  Frenchy Pilou (PILOU)
10913.8 In reply to 10913.7 
Ah ok! That is not effectively exactly the same! :)

So maybe Line Web can works...
Rebuild the 2 curves (10 pts )
Lineweb Lines (between the 2 curves)
LineWeb again 3 points / Curves (between the 10 lines resulting previously)
Order of selection is necessary!

EDITED: 11 Dec 2022 by PILOU