Lsd is 1 of my favourite subject to learn, but bear in mind that i have no experience hands on, but mere theory.. So sifus here help me if im wrong kay..
Usually 2way is used in drifting because on off-accel, the wheels still spin together at same speed.. Its easier to drift than a 1.5 because with a 1.5, sudden off-accel will not maintain wheel spin speed on both wheels.. Meaning if u were to make a right turn while off-accel, the outer wheel (left) spins slower than inner (right) wheel.. This translate to lesser speed because the left wheel is slower, as the weight of the car is transfered to to the left, much grip is added..
With 1way, the speed is much2 slower coz the left wheel could even stop spinning..
2way has high tendency to understeer, so for normal road use with occasional sports driving, 1.5 is perfect, safety n performance wise..
I hope this explanation makes it easier to understand how it works..