In this work we present new results on the morphological and microstructural properties of GaAs-AlxGa1-xAs (x≈0.24) core-shell nanowires (NWs) epitaxially grown on (111)B-GaAs substrates by Au-catalyst assisted metalorganic vapor phase epitaxy (MOVPE). Optimized growth conditions allowed us to fabricate highly-dense arrays of vertically-aligned (i.e., along the <111> crystallographic orientation) NWs. The NW arrays were investigated by Helium Ion microscopy (HeIM) and X-ray double- and triple-axis measurements and reciprocal space mapping (RSM). We demonstrate that these techniques can be employed in order to correlate some intrinsically local morphological information with statistically relevant (i.e. averaged over millions-to-billions of NWs) data on the NW structural properties.