I've seen the flip-throw done two ways-

1) ball on ground, handspring with hands on either side of it and then grab the ball as the body comes around

2) keep the ball in the hand and do the handspring off the ball

#2 seems harder to balance (more dangerous).

is there any advantage as far as the distance/velocity of the ball?

I can see advantage of having ball in the hand already (both from the surprise element and the lack of a need to execute the "grab").

Appreciate any advice.

sorry, just remembered there is a soccer forum. I'll take it there.