can't give any feedback on videos it seems that you are just starting w/ fig 8. maybe try to create backspin so you can give feedback to us.
i'm not very experienced with the fig-8. it was one of my first styles, but what you don't use you lose...
pure fig-8 has a strange arm motion unlike other styles where the arm externally rotates and snaps back , in fig 8 it's more like an extension of the arm (tricep contraction)
lately i was trying to create backspin and after some thought and empty pouch trials i concluded that the fig-8 is the best way to throw a backspin.
tried it on a football field w/ tennis balls: 50m w/ headwind,80m w/tail wind, in both occasions trajectory was flat with a drop at the end. i wasn't too consistent w/ it .
tried backspin fig8 w/ stones @ close distance and i'm worse, they go all over the place or they spiral instead of backspining. i guess i need more training?
i want to incorporate it in my training but i'm afraid it's gonna mess with the mechanics of the other styles.
also undecided on the effectiveness of it's mechanics(i don't like the follow through), could it be just better to spend more time perfecting spiral instead of playing around w/ backspin?
if i use it w/ stones @ long range it will show if it's effective
we'll see....