Just for reference and my own experience with a 13 F150 Eco MaxTow..
I had a #5000 GVWR 2003 Prowler Lynx TT that weighed every bit of that GVWR. (I pack heavy on purpose)
Started towing that trailer with a 97 F150, 5.4, 3.55 gears. Did fine for what that era truck was.
Got the 13 and it towed that Prowler with ease. I used "Regular" fuel too. (87 octane).
Fast forward to 2019 and we get a new #7000 GVWR Rockwood.. First tow with it on the same route we have been taking for years with the Prowler, there was a significant difference in it's towing performance compared to what I was used to.
It handled the trailer just fine, I just found I was lacking power for some reason.. Normally, I could take the grades in 4th and have lots of power left and not run the coolant temps too high. (I have an ODBII monitor, so I can see the actual coolant temps, not just the dummy gauge on the dash..)
I found I had to run in 3rd to keep the boost in check and the coolant temps and slow down. I also got worse mpg's than I was used to.
Before the next trip, I ran Premium (92 octane) fuel for at least a full tank, and then pulled the same basic route again (going over I-90 and the pass) and I was back to my expected performance. Back to 4th on the grades and still having to watch the boost and the coolant temps, but very manageable and able to keep the prior speeds and extra performance I was used to.
I also saw my towing mpg's get back to the 9-10 mpg range and even my non towing mpg's seemed to go up an mpg or two.. So, I've been running the Premium fuel all the time now and the truck really seems to like it and the extra cost is not really that big of a deal for me..
Anyway, I have loaded my trailer to where it's at it's #7000 GVWR too, as I said, I like to pack a lot of stuff (full water, more stuff than I'll ever need, but that's just how I roll.. Judge me if you must, but I don't really care. :) )
As said, watch your other weights like payload and especially rear GAWR. I have #4050 rear GAWR and probably pretty close to it when it's all said and done.
Good luck! Mitch