Currently there is no automated way to use peak element loads for panel buckling in HyperSizer v7.0. The panel buckling analysis always uses average compression Nx, Ny and Nxy.
You could look at the Critical load cases section in the stress report and extract the peak element loads for each component, then push them back in as user loads to size each component for buckling. For any component in an FEA project, you can switch from FEA loads over to user loads on the Free Body tab.
-James