I'm attempting to access package variables dynamically

That sounds like you are saying you want symrefs.

but my monk mojo is not strong enough yet understand it fully.

Symrefs are found in the fobidden books. If you read about them I strongly recommend that you do not lick your fingers when you turn the pages.

 # I need help getting the next line to work properly
 next unless exists eval { %{$normal{$col}} };
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Note the syntax of dereferecing symbolic references is exactly, completely, totally, 100% the same as the syntax for real references. You shouldn't consider using symrefs until you are well experienced in Perl, and you can't be well experienced in Perl without understanding real references.

In other words in the above code you have a sympolic reference $normal='my::model::subclass::normal' but you can dereference exactly as if you had a real one $normal=\%my::model::subclass::normal.

No, seriously, telling you how to get that line working with your current level of understanding would not be helping you.