I'm guessing most people on TRP do 5x5 SL, because most of the people I met before I started lifting told me to follow that routine as it gives you strength as a beginner and constructs your body and your form.

Q1: When and should I start following the 5x5 SL routine with more arm work(dips 3x10 on mondays and chinups 3x10 on wednesdays)?

Q2: Why do some(?) people when doing deadlifts have one of their hands straight forward and the other one inverted? eg. https://i.ytimg.com/vi/Eo5Rc-9Z3EQ/maxresdefault.jpg