Hi ​@JDB 

The error message you're encountering "Exception: Service Spreadsheets timed out while accessing document with id...", is a known issue within the Google community and is not an issue related directly to our product. 

You can find various resources and threads online mentioning this very issue however there is no clear reason provided by Google about the causes of the issue. Based on feedback from affected users in the Google forums, it seems you're likely hitting one of Google Sheets' limitations apparently.

That said most of the suggestions from Google support reps in the forums involve reducing the spreadsheet size and the number of cells being populated and this could be achieved by reducing in turn the size of the result set being loaded into the sheet, either by decreasing the number of rows, reducing the columns, or both. 

1. Could you try reducing the number of unnecessary columns being inserted into the Google Sheet and see if it makes a difference? Clearing out columns that are not immediately necessary can significantly improve the performance of the operations running in the background.

2. If the issue persists even after reducing the number of the unnecessary columns, instead of retrieving the entire dataset in a single query execution, could you kindly try fetching the records in batches by applying the LIMIT and OFFSET operators in the Custom SQL query.

Let us know if the above suggestions are of any help.