>2-word compound modifiers and suspended hyphens

I have been taught that when creating compound modifiers, a hyphen (-) should be used if the compound consists of two words, while an en-dash (–) is used if the compound consists of three or more words:

I am Vancouver-based journalist.

You are a New York–based journalist.

She is a Rio de Janeiro–based journalist.

I have also been taught that when listing multiple compound modifiers that share a common base(?), one can use a suspended hyphen to avoid repetition:

He is a Canada-, US-, and Brazil-based journalist.

My question, finally, is how these two rules work together. Are the following sentences correct?

I am a New York– and Vancouver-based journalist.

You are a Vancouver- and New York–based journalist.

She is a Rio de Janeiro–, Vancouver-, and New York–based journalist.

Solution 1:

You are, of course, correct in your usage of en-dashes to connect a prefix to a proper open compound (I'm surprised this is not more generally known). Your solution of mixing hyphen and en-dash is a good one; style manuals will vary on this (if they consider it at all). The U.S. Government Printing Office would have you write U.S. with the periods (U.S. Government Printing Office Style Manual, Chapter 9 - Abbreviations and Letter Symbols).