My perezdelarosaes always flower in early spring, never in the fall. In my opinion they need a lot of sunshine, this also minimizes etiolation. My plants flower quite well, a ring of flowers every spring.
When growing older, these plants form offsets, just like the strongly related M. bombycina. My two oldest plants were sown in 1989 and they have 20 or more offsets.
In nature, the plants stay small, 5 cm high at most. There they also get a lot of sunshine, growing in ridges on well-exposed rocks. I visited two locations, but did not observe offsetting plants. In contrast, M. bombycina forms large mats in nature, just like in cultivation.
Subspecies andersoniana stays even smaller in nature, only 1 - 2 cm diameter. I do not know how large they get in cultivation.