Answers for "how to tell tkinter to find the best sizew"

set window size tkinter

# Change window_name to the name of the window object, i.e. root
window_name.geometry("500x500")
# To ensure widgets resize:
widget_name.pack(fill="both", expand=True)

tkinter max size

from tkinter import *
root = Tk()
root.maxsize(height, width)
root.minsize(height, width) #(69, 420)
root.mainloop()