I took Spanish-for-Spanish-Speakers in public school so my experience may be different.
“Spanish-Spanish” (Castillian-Spanish, Castellano) is pretty easy universally understood and accepted as a “proper” Spanish. It seemed to work well despite our mixed nationalities in the class (Cuban, Dominican, Puerto Rican, Colombian, Venezuelan, Nicaraguan, and a few more but those are first that came to mind.)
I took Spanish-for-Spanish-Speakers in public school so my experience may be different.
“Spanish-Spanish” (Castillian-Spanish, Castellano) is pretty easy universally understood and accepted as a “proper” Spanish. It seemed to work well despite our mixed nationalities in the class (Cuban, Dominican, Puerto Rican, Colombian, Venezuelan, Nicaraguan, and a few more but those are first that came to mind.)