First I'd like to say this is my 100th post! Now I've been meaning to transplant the Adenium for a few weeks but just got around to doing it today. This is the last day of my summer vacation so I figured I should do it before my free time disappears for another 8 months. I used a small shovel to dig them out of the pot. Most of them had a chunk of dirt around their roots so I could simply place them on the soil in their new home and then fill in the sides. About 1/3 of their taproots were slightly damaged, but this is supposedly a very resilient plant.
I ended up using a mixture of potting soil, orchid mix, vermiculite, sand and a very small amount of manure. There are many different mixes that should work but it is important to keep a ratio of about 1:1 water retention:drainage.
I have limited space and finances so the new container is an old window box with cardboard dividers (to reduce root intertwining). Each plant has a 5x5cm (2x2in) cell that is about 10cm (4in) in depth. They shouldn't need to be moved for about 2 or 3 months.