Question: I've changed my mind a number of times about which of these variants works best:

1. > 
> the **second most northerly** coffee shop in Seattle
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> 
>
2. > 
> the **second-most-northerly** coffee shop in Seattle
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>
3. > 
> the **second-most northerly** coffee shop in Seattle
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> 
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4. > 
> the **second most-northerly** coffee shop in Seattle
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>

I've tried to do a little research, but I'm not even sure what to call something like this, so I haven't had much luck.

Any guidance on what is considered most clear/correct would be much appreciated!

Answer: 
A hyphen should be used to force the parsing "(second most) northerly" rather than "second (most northerly)". Thus, it should be "second-most northerly".
Surely the primary variable here is the 'northerliness' of the coffee shops' locations. Consider the following:

> 
> '***The Coffee Cup***' is a coffee shop in Seattle.
> 
> 
> '***The Barista Bar***' is another coffee shop in Seattle.
>  It is further North than '*The Coffee Cup*'.
> 
> 
> '***Luscious Lattes***' is another coffee shop in Seattle.
>  It is further North than '*The Barista Bar*'.
> 
> 
> 

The simplest way to make clear their relative northerliness is to say:

> 
> *Luscious Lattes* is the most northerly coffee shop in Seattle.
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> 
> *The Barista Bar* is the second most-northerly coffee shop in Seattle.
> 
> 
> *The Coffee Cup* is the third most-northerly coffee shop in Seattle.
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> 
> *etc*.
> 
> 
>