Yeah, it could be just because I've always gripped my sling that way, but I feel out of control when I grip it anyother way, particularily when the retention cord is outside of my hand. As for not hitting the ground, it takes a little practice. If you release too late it'll hit the ground. Also, you may want to experiment with shorter slings, if they are extra long, it makes it a little more difficult to use this style for low angle shots.

As for cord diameter, it's just standard para cord that I use.

Figure 8 Style continues to grow on me.  I found that using a sling longer than my 32" Greek Overhand sling helps make that first turn under the right arm.  I lengthened to 38" with good results.

I agree with Matthias that misfires tend to be in an easy to dodge vertical plane and low powered.  I am introducing some tennis players to slinging and bet that they will pick Figure 8 up right away.

I put that vertical plane to use on a utility pole and was rewarded with 2 of 4 throws giving a good solid "Thwock."  I'm sold!

AjlouniBoy