I don't really give a squat about symmetry (flaws show character).... I am going to heat it and bend it a little (might beef it up with steel so it won't flex too bad), so you won't see the difference.
I made it "flat" and "stretched" it a bit left and right, so that it looks a bit "wide" in the middle, and it will cover my hands on a cold ( I have the horn type bars) windy day and still serve as a wind break for the main section.
I drew the curves by hand and will leave it "as is", and will probably make the cuts a bit different than the marks. I plan to use a dremmel with a textured cutting disk (grinding) on slow or medium speed so if it melts it I can still sand or razor blade it off.
Since I am painting the backside black I am thinking of adding some led lights to the edges to see what it will look like in the dark.. LOL..
Like Old Feller says in his software and computer posts.... "changes, they are a comin' "......