Oh yes, asseliformis is gorgeous! And I like that they all stay so small.

Is you Stenocactus rather yellow?

Not right now. But there was a time it was more yellowish. I know I underfertilize them and I start to think this could cause lack of flowers. Not many of my cacti bloomed this year in general and they grow rather slow (I lost a few of my favourite ones and got a bit demotivated). They got some boost some weeks ago and hopefully next spring it will be better.