I'm sharing my session dedicated to learning double backroll kiteloop.
Wasn't really powered that day, not trying to do them Megaloop style lol, more like a slow late loop kind.
Anyway it's not a tutorial but what helped me nail it is to send kite fairly hard and "pop" early before kite reach 12 so first rotation is done before kite goes too far to the other side of window... once you finish first rotation crank the bar, you don't want to wait for half rotation because you will over rotate.
In term on when to send first rotation it's same timing as darkslide or backroll hand drag.
Main issues were not enough power
kite goes too far to side of window after first rotation
Loop too late which sends you in a third rotation...
I don't actually pop, don't want to go high just yet so I kind of just throw my leg around.
I think next step is to pop and slow down the first rotation...
get better at keeping kite overhead during first rotation instead of over sending it...
get inverted on second rotation would be nice too.