The first line is the size of the stack in bytes for each thread. So 197 is the total stack available to the first thread. The last number, 14581, is the amount of heap and stack available to the idle thread.
Nil RTOS fills all stacks and the heap with 0X55 bytes. The second line gives the "high water" size of each stack by looking at how much of the 0X55 pattern remains.
The stack grows down so the low 183 bytes of the stack for the first thread still have the 0X55 pattern.
14533 bytes of the heap/idle stack that still have the 0X55 pattern.
After you run your threads in a normal way, print the unused stack size. You can reduce the size of each thread's stack so the unused stack size is small. I like to have at least 32 bytes spare.
It appears that many of your threads hardly executed.