How much did portfolio margin requirements go up during the Great Recession/2008 Crisis?

I'm trying to do simulations involving leverage and want to plan for a worst case scenario for avoiding a margin call if Maintenance margin requirements were to go up to a similar level as during the Great Recession.

For more information:

1) I'm on portfolio margin

2) I'm holding broad-based index securities like Total Stock/Bond Indexes. I don't hold individual stocks.