Is it possible to use the dart tool to correct the lengths on curves?
I doubt it since the tool only accesses straight lines, but the best way to find out would be to try it. You could always undo the changes if you’re not happy with the results.
It does not work My approach now was to draw the dart into the bend and mirror a darting line. Then I put the curve in a group and my, in the case, have redrawn waistline