I have done it to dozens of decks
I don't like what he has done to internally ground on that video - I recommend grounding to BOTH rca shield terminals, not just one. The quickest, neatest and easiest way to do it is cut the existing ground cable back about 5cm from the board connection, strip the end and the middle of it, and solder the middle to the closest shield terminal and the end over to the other one. that way if one shield breaks, you have the other as backup...and it looks really nice too.