Respectfully, you will probably not find a better, more responsive forum than this one.
You have apparently posted a single question and it's on a rather obscure topic. Desert roses aren't classic, or even much used, bonsai material. Sometimes, you are on your own with some species and their use as bonsai. Others have little experience with the specifics of them in a bonsai container.
Also, sometimes the basics that are used in common bonsai species are still pertinent to exotic species like desert rose. You want thick surface roots, try the methods used to develop the same kinds of roots on other species. Might work, might not, probably will since the growing principals are the same.