Look for the cheapest stick in the rack.  Regular cornerbead.  At my Despot, the guys in the aisles (though few) are pretty knowledgeable and very helpful.

Listen; I'm not sure in the end how much utility this stuff will have for you. You (and Wayne) are shipping VERY large and heavy items, and your hardboard corners may be the answer.  For my little preamps and wimpAmps, it's The Answer, so I submit to your attention.

Besides, some of the drywall girls are P D cute!  ;^)

Aloha,

Poinz