To me that one looks good so far with it's nice fat caudex/roots. I think with time, proper light and proper water, it will enlarge it's canopy on it's own. I wouldn't be pruning it yet. Later on if the branches don't elongate, then I'd take a tiny bit off the end of each branch. These are very hardy plants, and pruning doesn't hurt them if it's thoughtfully done. it normally makes them better.
