JVM setting, specialy memory heap and gc, depends on the application and the JVM.
If you have the right heap size -Xms and -Xmx can be set to the same value, this is to avoid recalculating and allocate/free physical memory (Oracle JVM).
Less size of the heap might be end in a better performance and the JVM decide to not use the maximum of what you set.
So you should monitor the JVM and GC behaviour in production and adjust the parameters here. Also, from my experience, it makes no sense to tune with a lot of effort because change of the throughput can change everything.