Modify Custom Webflow Embed HTML Script

I have a script that pulls data from a Google Spreadsheet to Webflow using the Embed HTML feature. At the moment the script works by query columns A,B,C,D,E,F,G,H...Z after about 30 columns the script does not pull columns successfully. The script then builds an array using the index function. I need it so the script can query any column based on what the columns heading is in row 1 and so that it can go to over 1000 columns. It should not require that I manually program the array by each column. It needs to work by my specifying which column heaidngs in row 1 that I want. At the end of the project I should be able to successfull query rows and pull data to webflow from any column heaidngs in row 1 based on the user logged in (logged in user part of the script has already been done).