Based on the 4X4 guys I know , this makes perfect sense. :D
For optimum, traction you like a wider rim than tread to give a full foot print.
Look at what the 10.5 tire and drag radial guys are doing......that is clearly the way to go fast.
A narrower rim will make the sidewalls bulge more , so I don't think that is gonna help you , for clearance or hook.