I usually try to open up the middle so the main colas make a crown or circle in shape, all about the same height. This allows the middle to really bush out with the added light that is getting down through the canopy. The middle will fill out extremely quickly and catch up to the LST'ed branches. The whole idea is to maximize efficiency and amount of strong branches and lots of good sized colas. As long as you aren't using metal wiring or something abrasive you can pretty much use anything to train, tie, or hold up the branches.