I have many semperviviums, all in pots of all sizes. They are lovely and live through everything. I made the soil poor and free draining by adding lots of horticultural sand and grit and I put some grit on the top around the plants.
I have 4 large heavy wide pots, holding a cantilever umbrella in place, they are filled with pebbles but I have decided to put semperviviums in, taking half the pebbles out, putting a garden membrane in and then filling with the same mix. I have JI2, sand and grit, so I will use that. I love the plants and they are so easy care