Flim (is there a Flam?) - Welcome!
I have Sedum hispanicum (plain - blooms white) and also the Purple Form. I'm afraid I've not paid attention to soil concerns with this one. For me, it grows like a weed in pots where I have some of my small fruit trees growing. When weeding the pot and I pull some up, I just toss it back or into another pot. I don't usually even bother with planting it. This one is very forgiving.
So it gets my basic pot mix, which is similar to Al's mix advocated in the Container Cubit(you may want to take a look at that). Basically quality potting soil with pine bark, vermiculite, perlite, and/or fired-Fuller's Earth mixed in. The mix varies a lot based on what is available at the time, but always has the potting soil and the pine bark as the basis.
Regarding growing conditions, because they are in the small fruit tree pots, they get regular water and are shaded a bit from the harsh sun by the tree above them.
I hope this helps.
-t
