That's about the thickness I always buy also.
I cook mine at about 6 inches from the coals. I use a grilling probe in the meat to tell me when it reaches the proper center temperature.
I use only enough coals to have one layer, where the briquettes are just touching and only directly under the steak, not covering the entire grill.
I leave the grill open.
Turn the steak only once at exactly half the end temp, minus the meat start temp.
Here's an example: If the meat is at 50 degrees already, and you want an end temp of 160, then 160-50 is 110. Half of 110 is 55. Add 55 to 50 and you turn the steak exactly at 105.
Sounds harder than it is. It's actually completely logical and I can vouch for it's accuracy. Mine turn out perfectly every single time. Done the same on both sides, right to the center.
For "Medium" doneness, take the steak off the grill when the center temp is 150F and let it rest for 5 minutes. The center temp will increase while it rests, to 160F.