If anyone on this forum is interested I did a comparison of the build size and performance of the same project with Wwise vs Unity Audio packages.  Basically I found out that Wwise is very light on the build size for the most basic features and was at least as good as if not better for game performance.  It's not a very scientific comparison and the performance testing is pretty light but I found the project a good way to start looking at Wwise and pretty interesting results.  http://www.zuluonezero.net/2019/08/18/unity-audio-vs-wwise/