This is a 1:1 scale 3D model of my velomobile. Scale it down to the scale you want using basic arithmetic. 1:12 scale means scaling it down to 8.33%.
I recommend orienting the parts as shown in the Simplify 3D screenshot. I stop the print just when it reaches the suspension arms and glue on the separate pieces. Print the body one side at a time, and glue the parts together for best result.