Hands can be close, medium or wide on this. There is no best, just don't do it the same all the time. Leave no stone unturned in your training.
When your arms are extended let your shoulder blades relax and spread out across your back, you should feel a stretch between/ around them. When you start to pull the handle TO YOUR FOREHEAD, start the pull with your shoulder blades pulling down your back and together. Once your shoulder blades are retracted and depressed then you can pull with your hands. Flare your elbows and pull the bar apart as you come back. Try to hold the bar at your forehead for a second. Let it out slowly keeping your shoulder blades back until the last second then let them stretch again before starting the next rep.
These are great for a warm-up where you can do light sets of 15-20. The scapular movement is good for mobility work as well. The best way to build mobility is through weighted ranges of motion. You can also use them as a 2nd or 3rd accessory movement and go as heavy as 10-12 reps. If the reps get any lower than that they tend to get pretty sloppy.
Put your thumbs around the bar, over the bar or pointed to the center to vary the grip stimulus.