One other note - once you have set up the points symmetrically you can then use the v2 edit frame to tweak those points pretty easily:




So you may not worry so much about getting the proportions perfect when laying out the initial construction line scaffolding, just get that relatively close (in general shape I mean but exactly symmetrical with the snaps) and then tweak with the edit frame.

This will again be easier with an actual full symmetrical editor helper, but this is another thing that can help a lot for now.

- Michael