Sweet spot for 4.10 gears

I've got the bullet proof vest on, shields up and ready. If this has been asked countless times before, I apologize in advance. What is the sweet spot for towing if truck has 4.10 gears and diesel? Test drove a '17 F350 that had 'em and at 60 mph, rom's were around 1850+/-. 70 mph = around 2150 +/-. Obviously compared to 3.55 gears about 300 rpm's more on both accounts.