To save you some time, here was a video of my semi-sumo pulling that I found just looking quickly. It looks like the first set was semi-sumo/squat stance and the second was conventional.
Like JM said, it was a bit of a transition from conventional to sumo. Sumo was much stronger and more comfortable for me (with a much better ability to grind), but it seemed to flare up my hip flexors. The squat stance seemed to be a bit of a blend for me. After I corrected some weaknesses (glutes/hams) I was able to pull sumo without causing pain, and haven’t switched back.