They work, but you can only put two QL Fans on one Spitty4. Because each RGBpx channel can light up tp 90 leds. Each QL fan has 34 leds. So two can fully be used, but the thirs one has only 22 LEDs left. So it's not fully working. And if you want to configure each led part on it' own (front outer + inner, back outer + inner) you need a mass of led controllers. So you might run into limitations of your Farbwerk. That belongs to what you want to do.
But basically, it works. I have 14 QL fans connected to AC products.