so based on a quick google search a 3/8 lagbolt holds between 200-300lbs of pull out force when tightened all the way into dry lumber, do the math based on that, in theory YES a vertical alignment would hold more. But i wouldnt recommend storing the rack on one of those hangars in the open position, i would recommend storing them folded (this puts more of the load in shear and less in tension/bending)