Most wings will see max CL when the flaps are within a couple degrees of maximum aileron deflection. Beyond that you're getting more drag and might get less lift.
I forgot to set flaps before the second take-off in my -8. It was off the ground almost instantly and climbed steeply. Plane was light and it was about 32? OAT. An observer said he saw nothing but the bottom of the airplane. I had to hurry to get the flaps up before 100 mph IAS, or so it seemed. Tried no flap take-offs and found them more that adequate for any normal situation. Now I'll not use flaps unless runway is very rough or has loose gravel etc. Have only limited experience at max gross weight. More of that might suggest using some flap when very heavy. 69D has an IO-360 and CS prop. It's off the ground so rapidly and in such short distance compared to most aircraft that I doubt there's much need for flap use on TO. YMMV!
Technique is correct-- lift nosewheel and she'll just fly off. Scott, can you weigh in on why POH says 1 notch of flaps? That requires a pretty good trim change when you retract the flaps!
One notch is the best compromise between extra lift and extra drag. Full flaps may help the wheels leave the ground a little sooner but the climb angle and rate will likely suffer..... (accelerating with no flaps and poping them to full at rotation is a common bush flying technique for getting off short)
I can't comment for Mitch but in the case of the video of me making that take-off... that was a first flight.
On a first flight I do everything I can to keep things as simple as possible. During the flight I did slow flight approaching a stall with and without flaps, after which I feel comfortable using flaps for the landing.
In most normal take-off situations I use half flaps. The primary exception to that for me would be a gusty crosswind.