John in Kansas has a great idea of pre-stretching the strings. Even for a tub that you pull back on, I've found you don't want a lot of stretch. I can hit a lot of notes by changing tension on a regular bass string or metal bike derailer cable. Both have almost no stretch. On the other hand when i've tried weedwacker line there is too much stretch between the notes, and as a result very little precision.

Bottom line, is just like john says. You have to adjust the design to your playing style in order to get the best results for YOU.

JAB