From your pictures, it looks like you need to lower the hitch head about one hole to get the trailer to tow level. Level is just right but if you must be off a bit because of lack of adjustment, then slightly low in the front is preferred. Never tow with the front of the trailer raised because that will tend to encourage sway.
I would go back to the number of links that you started with as that restored the weight lost off the front axle of the truck when you hooked up.
As far as towing speed goes, the faster you go the more tendency to sway. The tires are most likely rated for a maximum speed of 65mph so you should limit yourself to that speed or below. I have been towing for years at 60-65mph and have never had a problem with either sway or tires.
The instructions that came with the friction sway control bar you have are correct. That handle is supposed to function like an on/off switch and not an adjustment device. You are supposed to tighten that top control as far as it will go and then back it off until the handle is parallel to the Trailer A frame. Doing that will always give you the same amount of sway control. Any adjustments to that amount of sway control are done with the small bolt located at the bottom of the bar and below the large handle. You turn that adjustment bolt in 1/4 turn increments to adjust the amount of friction/sway control.
We have an excellent sticky at the top of this forum that will help you set up your hitch if you feel you need it. It is located
here.
Hope this helps you a bit. :)
Barney