Hi, I bought Li Ning Digital ECP Stringing Machine. My questions are as follow : 1. What is the pre stretch function? What is the purpose and the importance of using that function? 2. If i want to do 4 knots, how can I cut the strings into 2 pieces of main and cross string? 3. Do I have to starts a knots for the start of the stringing? 4. Do I have to increase 2 lbs on cross section? hope you people can helps me out! Thanks in advance!