Hi @zornzack,
One thing to know about solid shell: It is a precise mathematical offset surface. This can be good (you are guaranteed exactly uniform wall thickness), and bad (it fails for complex geometry). One tool set that can help here is the analysis tools, under the "Inspect" menu:

Two tools in particular, Zebra and Curvature Map can help to show areas of very high curvature, or surface discontinuities that exist in your model:
Here is a random shape:

Here is it with Zebra analysis:

where the stripes are dense indicates an area of high curvature, and possible problem areas. Where the stripes don't line up indicates a discontinuity.
Gaussian curvature analysis is also useful:

The red end of the spectrum shows areas of high curvature.
Most likely your model has some problem areas, and shelling is going to be a problem. Sometimes you can fix the model so to eliminate those areas. Sometimes you have to resort to other methods (defining your own shell profiles and features to hollow out the inside).
As @LMD001 says, there's no substitute for the actual model.
Jeff
Jeff Strater
Engineering Director