Mid surface problem in workbench for static structure analysis
 

I work on a rack structure analysis. Because there are a lot of sheet metal parts (in complex shapes) on the rack to keep the structure strong, so I plan to use mid surface to for simulation to reduce the mesh size. So my question is, is it accurate enough if I use mid surface instead of using the 3D model?

I also check online videos about how to do it, most of them can explain how to generate mid-surfaces. But I'm not sure what I should do differently compared with using 3D models. My case is that some parts can be easily transferred to mid-surface, but others seem too complex to do so. So there will be 3D parts together with 2D mid surface in the assembly. For the contact, since they are not contacting with each other after using mid-surface, I guess I need to manually set the tolerance and then automatically search for contacts again is that right? What else do I need to be careful about? Thanks.