Okay so I'm definitely a newb to this. I only have to consider the tongue weight of the trailer? Not the 4500-6500 lbs of weight that I'm actually towing?Standard spec are 110 which translates to 2337lbs
So why trying to step up to 115 or 120 which would be 2679/3086? You've got 4 tires supporting the 5k SUV, and you can only legally add 700lbs of TW to the rear of it.... so you don't need any higher load tires.