Looks like you are LSTing right now. Try to get them all even in height, and they will grow evenly for the most part. The branch and where it merges with apical meristem will have a say in that, but you can always keep the dominant growth a bit lower to compensate.
you can use almost anything - thick enough so that it doesn't cut into plant. twine, twist ties, a stake, etc... bend a bit with finger/thumb to avoid snapping anything. multiple spots can help create a near 90-degree bend, if needed.