Hi @jan2re
first thing, you haven’t been able to make layer; due to your geometry doesn’t have any faces, in order to assign a layer your geometry should have faces. to do that if your geometry is stl file you can split it into multiple faces on simscale using this guide by @Ali_Arafat. but this works only for STL file if your geometry not stl file you got to get back to your CAD software.
and you should not use any of the result to validate the other design because they are totally different geometry which mean they are different study’s that will give different result. but you can compare each other to see which one of the design perform well. you can read more about what is Validation on these blog.
regarding the angle of attack you can do that by preparing your geometry with angle that you need or by allowing the inlet air to flow in angle ( find the vector component) and apply it on the boundary condition.
that what i think of for now.
Regards
Anwar