title: Importrange() where the source columns/rows change
body: <p>I have an <code>importrange("key", "sheet1!D" &amp; targetRow)</code> formula, but I also need the column of the <code>importrange()</code> to be dynamic too in case I add/delete columns in the source data:</p>
  
  <p>E.g. <code>importrange("key", "sheet1!" &amp;targetColumn &amp;targetRow)</code></p>
  
  <p>I researched <code>query()</code> language but being forced to use <code>Col1</code>, <code>Col2</code> etc instead of named column identifiers makes this useless for what I'm trying to achieve.</p>
  
  <p>Can someone help me with this? Easiest way to get column letters without a script? Thanks very much. </p>