Thanks @Jon Schwartz
Would love to take a look, will send you my email under separate cover.
Not sure if you're familiar with the Missouri Census Data Center Geocorr application (I wasn't) but I came across it recently in support of another project I'm working on. It uses Census data and makes searching a bit more accessible.
In and effort to get greater clarity on what zips comprise MSAs, I spent some time on the Census site trying to work with the ZIP Code Tabulation Area (ZCTA) to Metropolitan and Micropolitan Areas Relationship File, but that doesn’t have the level of granularity I’m looking for.
I ended up using the Missouri Census Data Center Geocorr application (http://mcdc.missouri.edu/applications/geocorr2018.html) to get a list in my 'dream scenario' of Metropolitan and Micropolitan Areas Relationship to ZCTA (e.g. Miami – zip1, zip2, zip3, etc., Omaha – zip1, zip2, zip3, etc.)
Here's how I did it:
Select State(s)
Select Source geography: Core Based Statistical Area (CBSA) -- (found under both 2010 and 2013 geographies)
Select Target geography: ZIP/ZCTA
Select Run Request