Use the AS5 to make a thin line down the center of the IHS, but do not spread it. The force from the heat sink plate will spread it evenly.
After you have your CPU in its socket, and the AS5 in place, try to line up the Tuniq and its gold pins as best as you can with the holes in the MoBo before you make contact between the CPU and the HSF.
When you go to tighten the pins down, make sure you use small turns on each pin going diagonally (one corner to the next). DO NOT tighten one screw down before the others. This will make the Tuniq pop up and lean to one side, which allows air to interfere with the already-applied AS5, which then makes you have to re-apply and re-mount.
Also, make sure you don't over tighten the gold pins. In my first attempt of mounting my Tuniq, I tightened the shi
t out of the gold pins. About 5 minutes in, the head of one of the pins shot off like a bullet. Now I find myself looking for a replacement screw
Good luck & I hope this helps!