Dont forget that Jason is a tall guy. Pornhub have him at 6 ft 5 or 196 cm height, so his hand have to be bigger than average.
My PE technique is only manual stretching. In two years i have gained 1.5 inch in length. I went from 6.5 bpel to 8-8.1 bpel. Frequency per week was for the most part 5 days and two days of rest. The sweet spot in terms of duration is between 25-35 mins total time every day. Although i have made big gains in a period when i stretched for 1 hour every day. It depends ,but you have to build it gradually, because if someone is new to this, he should start with 5-10 mins and low force.
That's a quick summary and many other factors are important to maximize efficiency.