I love the pictures showing the subtle changes in your plant over time.
These plants enjoy lots and lots of sun at an young age (maybe 6 inch pot size, when you repot). In our mild climate they do not go dormant in the summer if the roots are not being cooked by the sun... I nested one pot inside another and the results were very good. I would think lots of sun is better, especially in fall/winter. You cannot provide too much light at that time of year.
You will note a change when the plant is in active growth where the top of the stem turns green. Probably around the time the plant shoots out another one of those skinny branches, this fall or winter. Like a smaller, younger version of this:
And that's when most of the stem growth occurs.
But yes these plants do well in reasonably small containers for years, presumably because they grow in cracks in the rock in nature and are adapted to small spaces (until they crack the rock or pot open).
