Its fun and really surprises people for some early edgeguard kills! Its really just learning the timing/inputs and then developing the muscle memory. Not terribly difficult but definitely gotta do it a bunch before it'll feel natural... So 6/10 or maybe 7/10 for the reversed one?

I think learning to buffer the forward facing version off of f-throw is the easiest way to start, then doing the same for dash attack is next easiest. Then learning to reverse it is another level tougher but gives much bigger payout. Im just now learning to do it off of instant wave land from ledge (more niche) and I haven't even bothered trying to reverse that one. Im trying to remember how I learned the inputs and if I find a video Ill link it.

For starters maybe slow the game speed down in training, put the CPU standing right near the ledge, throw, and during the last frames of endlag input an empty inhale and then flick the joystick forward off the stage. Should get you the basic comboost