Revisiting this topic.
There is a Show-Me video on Event Budgets for PO. Based on the video, I was able to copy the GL budget amounts for various GL Account-Dept’s over to the PO.
In the Company Profile, I set the system to not permit posting when we go over budget.
I have managed to do this in PO and it appears to work.

And you are correct, Dan.
If we adjust the budget amounts in the GL, then yes, we have to re-import the GL budget values into PO. Otherwise, the incorrect pre-adjusted values remain unchanged in the PO module.

Here is one question that I am unsure about: What happens when the new fiscal year starts up?
Is it possible to get the PO Events to adjust to the new year, and start counting all over again?