There`s another alternative way to make a strong lake-slinging

fingerloop:
I don`t have a Photo for this but it`s easy to follow.
Take X strings for your main cord as mentioned in the beginning of this tutorial,
mark the middle,
add X short strings (the middle of them aligned with the middle of the main strings),
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start braiding some inches from one end of the additional strings over the middle until you have the desired loop-length, then fold the braid to a loop and continue as described in step 5 above.
Hope you enjoy trying this method.

Have a nice Xmas and please write some feedback. I´d be glad about opinions of other slingers.