The light you have right now is a fine vegging light. I have a 300 watt fixture currently set to 50% so pushing around 150 watts now.. you could probably put yours at 100% right now if it’s only 150 true watts. That wire you are talking about is the best to use, non abrasive and won’t damage your plants, super easy to use as well. Found some for about 4 bucks at my local hydro shop. Plastic pots imo are easier for LST as they don’t give when you tie down branches, however fabric pots work fine for this and supply oxygen to your roots for more vigorous growth. Your grow looks great though man! Just think, you could use your current light for veg and if you buy another stronger one, use it for flowering and you can increase the longevity of both fixtures and have them for years to come!