The LSD helps predictability. The car will, in essence, do the same thing every time. With the open diff depending on the loading on the tires, and a bunch of other crap, the car can act differently each time you come into the same corner which obviously means you have to back off more than you want until you see what the car is going to do.
Driving looking pretty good Mr. 5, you were actually doing Ok at the beginning of the slide, slowly feeding the car a small amount of opposite lock waiting on it to come back...problem is when the car passes the "butt accelerometer OH SH(T point", at which point people start sawing at the wheel. Resist the urge in the future and try to control the rear of the car a bit more with the throttle during the slide and you'll be all set
Looks like a lot of fun.