TFS SQL Server Report builder - Trouble finding Test plan ID parameter syntax

Modifying canned TFS reports with default values for date, iteration and Test Plan (for embedded burndown reporting against a specific project) Another article on this site led to a great report to pull the IterationID syntax that is needed within the parameter field (AreasAndInterations.RDL on OneDrive).

I'm trying to locate a similar report (or a query) that will provide the syntax and values needed for a default "Test Plan" to load within the RDL report. Thanks!