I traced half of a symmetric image, cloned/flipped the object and joined the end-nodes. Now I have a single filled path like I wanted, but any edits I make will break the symmetry.



I basically want to pull a bezier handle on the right and have the one on the left mirror the same action.

If Inkscape isn't capable of this, can you suggest another workflow for working with symmetric shapes? I'd want a clean SVG output (single shape for both sides) and maintain the ability to go back to any shape and adjust the curves without breaking symmetry. The only way I can think of is incredibly slow, because I've got to break the curve, remove one side, copy the one I've modified, flip it and join them again after each change.

All help much appreciated.

Welcome aboard!

Instead of copying, better to use duplicating (Ctrl+D),
or, in this specific case, you better use cloning instead (Alt+D).

That way, it will correspont immediately to your edits on the parent object,
however you will need to release the clone link (Shift+Alt+D) and combine it (Ctrl+K) with the original path, and connect the right segments at the end.

On a side note, the node in the middle on your image is not symmetrical.
There is an option on the node editor tool's toolbar to merge nodes, which can make it right.