One of the issues in using Instant Meshes is trying to control the overall orientation of the splines. We would like to have a horizontal / vertical orientation wherever possible to make it easier to set up bones and constraints in A:M. I am sometimes able to get this orientation, but I do it by pushing the buttons and etc. (without knowing how) until I get to the final result. The examples below show the original .OBJ imported to A:M, the default by running Instant Meshes without any modifications and the better final result after fiddling with it. The -steep creases- button seems to help in some cases and the -align to boundary- button seems to help in other cases.