Hello mkamradt,
You mention you came across the parameter “NumCookersToSpawn,” and I am having trouble locating the exact function to better understand the context of what it is actually doing. If you want to reduce build times for your project, there are a lot of different options in doing so, without having to use this parameter.
Take a look at our documentation on Content Cooking options. There is a parameter named -iterate which Specifies the cooker only cook items that are out of date. Without this option, the sandbox directory is deleted and everything is recooked. This will definitely help with cook times.
Content Cooking
Let me know if you have further questions.
Thank you,