Hi fellow F150 owner.. Mine is a bit older, and quite a bit different in GVWR, but the axle ratings are probably about the same.. (specs in my sig)
With that said, I've been towing TT's with a couple different F150's since around 2002 and towed all kinds of other stuff since I was a teen.
Anyway, that APEX looks like a nice rig. It's GVWR is the same as my Rockwood (#7000) but it's a tad bit longer 31' compared to my 26'.
Depending on your prior towing experience, going to a heavier, longer trailer will feel a bit different, but should still be 'comfortable'.
The slight bucking feeling can be many different things.. If it was an empty trailer, it'll tow different once you get some weight in it and more tongue weight can help with a lot of that 'sway' kind of feeling.
I run my gain on the OEM controller at about 8. It won't lock the brakes on the trailer even at 10 and I don't really want it to.. At 8 it does a fine job and you can feel it pulling the trailer when applied.
How much you can turn will depend if you have the WD bars on or not.. If you have the Equal-I-Zer brand, those set on L brackets and depending on the setup, they could come off the bracket if turned too sharp. When I was a kid, we had that setup on our TT and Dad turned too sharp and one of the bars slipped off the bracket. It was almost jack knifed and could not be helped, but the bar still came off. (this was back in the late 70's)
I take my WD bars off before I park the trailer at home. I have to twist and turn and at a sharp angle getting up the curb where I park it..
I'd pump up the tires to the max psi on the tire when towing. Sounds like your's are P rated and might be a max of 40 I'd guess. I got 'XL' rated tires which are good for 50 max psi.
I've done some additional suspension mods to help out with towing. Yes, I know they don't add to any payload or weight ratings.. They just help the overall package.

In the end, it takes a bit to "dial in" a new rig and might take several trips to get it all worked out. It'll never feel like "it's not even there" kinda thing, but you can make it so it'll be a comfortable tow in the future.
Good luck! Mitch
