This is a Monte Carlo Simulation exercise; however, you are approaching scenarios too simplistically, in my opinion. You are creating very simple if-then scenarios in which you can make a very simple but inaccurate calculations. For example, doubling your staff will decrease your duration in half, assuming a linear relationship between work, duration, and resources. You can make a similar calculation reducing your resources' utilization by 20%.
However, work is not this deterministic. In fact, you have hundreds of probabilistic variables banging up against each other with varying degrees of cause or correlation, INCLUDING aleatory variability. Using Monte Carlo simulation, you would load in the tool your assumed distributions for the variables at play, e.g., costs, resource utilization, time, etc. The tool will run thousands of simulations randomly choosing a a value within those distributions and produce a final result on whatever metric in which you are interested.
The resulting distribution, say on costs, is far more valuable to you for planning purposes and risk management then a simple calculation that says, reducing 20% in resources will cause x% increase in time. That is a deterministic result that has an extremely low probability in occurring.