11-13' is really high. They are going to be difficult to control (balance, wind) at full extension. Do you really need that height? If so, the PCB stands might be the way to go, though I don't have any personal experience with them.

I really like my Lowel KS 9' stands. I've had them for 30 years. They are easy to transport, sturdy and can easily handle a medium sized light or light modifier. They can handle a sandbag or two as well to hold it steady. Get used ones on ebay cheap. Another choice for sturdiness and height would be a C stand. Heavy and a bit awkward, these are the gold standard for holding stuff up-- fixtures or light modifiers. A gobo arm adds additional height and versatility. Drop a couple of sandbags on it and it's not moving anywhere. Get some with the so-called rocky mountain leg for uneven terrain.