I grew it last year and I got some smaller stems like the tender stem broccoli you can buy. It is not hugely productive though, so I have ditched it. I also tried the sprouting cauliflower cross - that was useless.
If you want tender stem veg as a sub, stuff like Kailaan is more reliable, especially if you grow it under cover. I have pots of it in the unheated greenhouse over autumn and winter and use it as a cut and come again crop. You often see such crops described as flowering cabbage or kale. The original varieties are better than the hybrid crosses with our outdoor brassicas in my view.