If I understand this correctly, I think Roy is right: that is going to pull apart. The only thing holding one of the sides of the loop is the friction of the bundle on the other side of the bundle, and that friction is only due to the tightening of the serving. It is not enough.
For argument's sake, if I *had* to make a string like that, I would make it 3 or 5 times the required length, then fold it in 3, or 5, and use the bends at the end as part of the loops. That way, some of the stress would not be supported just by friction, and it just might hold...but even so, you would either have to use many strands, or it would fall apart slowly after several shots. Remember, the string suffers severe vibration and rapid stress variation, and it will shake itself loose given the slightest chance...And it is dangerous to break one.
Overall, I`m with John: why bother? String making gets a *lot* easier with practice, and quicker and better too. A cheap serving jig also helped me tremendously, both in diminished effort and faster job completion. I'd stick with the standard types...just my opinion. However, if you decide to persevere with this, best of luck, and keep us posted on your findings. Who knows? you might be on to something!
DF