If you have a calligraphy function to see, use it.
I normally define my stack requirements as configMINIMUM_STACK_SIZE+xxxx
Where xxxx is my estimate of what the task needs to do its own stuff. Check carefully for buffers declared inside tasks on their stack.
Also, turn on Stack Checking so you have a chance to get warned of stack overruns. It doesn’t catch them all, but can help.