Constants to be managed at developer level

Hi all,

I am developing a Sales Dashboard that is containing also variance analysis for the different Account Managers. I have made a very "dynamic and customisable" version where I can select multiple scenarios for Actual, Budget and Forecast with related Fiscal years but I would keep this version for central use.

With the same dataset I need now to build a more "closed" version of the report with a couple of variable (or better constants) to be manged centrally by me. For example I would like to define the "Current FY" and the "Open period" in order to present meaningful results to the users.
Practically a few parametes decided upfront. What is the best way do do this?