Thread tension for free motion quilting

I belong to various Facebook groups about quilting and see a lot of people asking about thread tension and when I see them I would like to give them answers but various things affect to thread tension and I don’t know what is happening there and for that reason I don’t write anything there(as well as there are plenty people writing some answer anyway).
But here I am writing if somebody needs some help.
 
While free motion quilting, what determine upper thread tension is the setting on a machine and how you are quilting and those are my guesses of what affect the latter.

How fast you are stitching.

If you are stitching slowly, your movement of quilt more likely to affect to tension because you have more time to pull.

How fast you are moving quilt

If you are moving quilt faster, you are pulling thread harder so tension increase.

Which way quilt is pulled

Pulling certain way adds more tension.

Thickness of quilt – edited in

Thread tension is controlled by tension discs and presser foot. When material is thick, presser foot will be slightly placed higher and that loosens the thread tension. When presser foot is pushed up by thick parts of quilt like bulky seam, thread tension get loosen and may cause eye lashed on the back.

And this is very difficult to control. Luckily my free motion foot has screw to change the height as I want any time but most of foot don’t have this. Just be aware because sometime this cause big mess on the back.

I think we all learn and improve above things by experiencing it. But if you can set your machine better that helps too, dosen’t it?
The general rule is to loose upper thread tension which I have no argument with. However I needed to loosen it considerably to make it reasonable and my machine didn’t control tension with that setting very well. To resolve that, I tightened bobbin tension and loosened upper tension somewhere else. Here is how.
I have two bobbin cases, one for normal sewing and one for free motion. One for free motion is set to tighter.
They are identical bobbin cases but one’s latch stays like that in this picture if I don’t close it and that’s how identify them. In most cases, mark one of them to know which one is which.

 
My machine is Janome 1600P, semi industrial machine and have an extra thread tension control nob and a set of holes.
This one is tightened for normal sewing as it says on the manual, 5mm of screw thread should be seen.
And I loose it by two full turn for free motion.
 
This is how it should be threaded for normal sewing, use two holes.

I use only one hole for free motion.
The result of above is I can change main thread tension more flexibly. I can tighten or loosen a lot or just a few notch. Also tension discs have better grip on thread since it is somewhere in the middle.
 
Then I adjust main thread tension depending on thread and how it’s quilting. But as I said at the start, there is another factor to the tension, human and I can set it to be just reasonable on both side.
This one is front side and I can see bobbin poking in some places.

And this one is the reverse side of above and I can see top thread poking here and there too.
I am happy with that setting and I can live. Maybe I am not trying enough to fix it.
If you have any good advice, please let me know!