Not sure of the Tianya system, but they should work similar to cokin's..
if your front filter rotate during focusing, then the filter will rotate, but the holder is mounted on a disc which allows you to rotate the angle of the filter so you can adjust it..
It's best to direct your questions direct to tagotech.
They are thicker than Cokin, so if you use Cokin P series 3 filter holder, they can still be used but not the center slot, its really hard to insert Tianya into the center slot.
I recently bought ND4, ND8, GND and Orange GND. Holder and ring wise, I use Cokin.
The ND4 is ok, 2 stops, but the ND8 is 2.2/3 stop instead of 3 stop, but not a big problem. The GND is about 2 stop, the Orange GND is about 3 stop, results may vary as QC not consistent. Also my OGND like not very evenly applied in the horizon.