Update :-) my 4$ window fix just failed after 4 years and 8 months :-) on the driver side , passenger side still ok :-) but I will replace that too
sorry I did not reply to the questions how long is that bungies what I used .
I think it's will be different for every car . Have to play with it a little bit and find the right length :-) that is how I did mine more than 4 years ago .