Air it up until the base just lifts up, then position the TT on it as to center it, so the clearance between your shelf & Air Mass is even all the way around.
I have a CDP set on a Big Rock 3 which sits on an Air Mass 3 and there's about 1/8" clearance between the bottom of the Air Mass & the shelf.
I have a CDP set on a Big Rock 3 which sits on an Air Mass 3 and there's about 1/8" clearance between the bottom of the Air Mass & the shelf.