I would expect this approach to work for sizing for laminate strength, local buckling of the members (i.e. of the span between stiffeners, the blade itself, etc), global buckling of the panel, crippling, and crippling/buckling interaction. The piece of the puzzle that will be missing is any kind of sandwich failure mode such as wrinkling, crimping, dimpling, or any of the core failure modes such as core shear strength. For purposes of being placed in a laminate, a core material is used for to introduce a gap between plies for bending stiffness, but for the most part is treated as a void. So it does not contribute to in-plane stiffness and is not included in the failure analysis.
Therefore, the thing to be aware of when using HyperSizer for this type of panel is that it will not tell you anything about which core material you should use or whether the members will fail in any kind of sandwich failure mode.
When you say you haven't had much luck getting it to work, what are you referring to? Is the code having a problem? Or do you not know which options to choose to make the panel type you want? If that is the case, I can help with that.
