What is the best QB report to run to determine a net credit sales amount for a period of time for purposes of calculating Days Sales Outstanding (DSO)?

We can pull up the Sales by Customer Detail Report, @vconger-thehunle. 

The Sales by Customer Detail report shows all sales, regardless of whether the sale involves an income account. Let’s customize the report to help you get all the details you need within a specific period. 

Here’s how:

1. On the left pane, select the Reports menu.
2. Search Sales by Customer Detail from the list or in the finder.
3. Click the Customize button.
4. Set the Report period and choose the Accounting method.
5. Go to the Filter section and select which ones you’d like to appear on the report.
6. Press Run Report.

To learn more about the process above, check out this article: Customizing Reports. 

You can also memorize it to save its current customization settings. It serves as your record and helps you quickly access it for future use.

I'm also adding this guide that contains details about the days sales outstanding along with its calculation: How to calculate and improve DSO.

Don't hesitate to let me know if I can be of additional assistance. I'm always here to keep helping. Have a good one!