Should be a easy tow. I pull a 7500lb travel trailer and while noticeable it's not to bad. I have the 3.5l eco boost. Wind is the big issue and you won't have that issue with a flatbed.
I am getting 10-11mpg with my 28ft trailer as long as I'm not climbing mountain passes. I think the frontal area and shape has more to do with mpg than weight in most cases.
At 28ft and 7500lbs this is as big as I would go with a f150. If you want a easy tow more like a pop up, stick to 19ft or less. The truck has plenty of power and braking, but things get crazy when windy out.
Put defender 275/60/20 116H XL tires on yesterday. Replaced the oe hankooks and there is a very noticeable difference in ride quality for the better. I didn't notice a harsher ride at all, But did notice better cornering and handling. These tires no longer feel like they are rolling over in corners.
By tilting the ball back you might unload the rear of your truck too much. If you have a panic stop you could easily jack knife your rig. Make sure your weight distribution is within limits. Normally 50-100 percent.
Changed my battery from H6 to H7 Walmart battery and installed a monitor to tell me if it is below a threshold I set on the monitor. So far no issues. I drive my truck maybe once a week 10 miles...