This video has been making the social media circuit. Personally, I find it disturbing and don't recommend that anyone use it as a teaching example. The pilot is clearly flying this seat-of-the-pants and making it up as he goes. There are so many factors involved in a successful turnback, and practically none of them are shown or discussed. Videos like this give the wrong impression. The turnback is a high-precision maneuver with numerous factors many people aren't aware of. Boiling it down to altitude and a quick, steep turn is woefully inadequate.
Both videos in this thread bother me but I am particularly concerned with the emphasis on getting the aircraft slow and with full flaps out in the second video. Full flaps usually add more drag than lift and don't do good things to the glide ratio. That's true in spades for the large fowler type flaps on many single engine Cessnas.
I'm not a big fan of using flaps unless you actually need them and certainly not when using them is counter productive. If you've got two or three thousand feet of runway available, flaps are not going to be required to land the average GA single (and there's no reason to fly it like a 737), and adding full flaps will reduce the glide ratio significantly and adding any flap at all will have an adverse effect on it. Landing in the trees at a lower full flap airspeed is still landing in the trees - and far worse than safely making the runway if that is possible without flaps in a given scenario. It's even preferable and far more survivable to run off the end of a short runway at low speed after a no flap landing, than it is to come up short and crash at your flaps out stall speed in the trees short of the runway.
Turn rate and radius are important in a turn back to the runway after engine failure, and increasing bank angle and reducing airspeed with increase the rate and reduce the radius of the turn. However, without power, you'll be trading varying amounts of airspeed and altitude to provide the energy needed for that steep turn. In addition, the greater the load factor, the higher the AoA and the greater the induced drag penalty, and that has to be considered in the airspeed versus altitude loss decision. There's a balance in there somewhere, but getting a light single engine aircraft slow and with full flaps out after a 60 degree banked turn isn't it.
For example, if your stall speed is 51 mph and your best rate of climb speed (and best glide speed) is 69 mph, a level 55 degree banked turn gives you a 30% increase in stall speed and brings the 51 mph stall speed up to 66 mph. Based on those numbers and the need to balance the rate and radius of the turn, with altitude loss and best glide speed, I'd stay with a bank angle that does not exceed 55 degrees while maintaining the best glide speed, until I know I have the runway made.