Thank you doranchak,
Added a colorful UI with some basic options, plus/minus keys to increase/decrease threads, 0=pause. u/i keys to increase/decrease keys per cipher. It shows all kind of handy stats, pressing the x key will exit the program after letting the threads finish and generating a text log in the results directory + a screenshot of the window in the root. Fixed some minor problems here and there.
I have stress-tested the program up to 125.000 ciphers (30+ hours of computing) and nothing went wrong. I'll update the main post with some extra information about the UI as soon as I have some more time.