APEC WATERSystems SADDLE-DRAIN-3-8 Drain Saddle Valve 3/8" for Under-sink Reverse Osmosis

When assembled, what is the inner diameter of this saddle valve? (no guessing-i need to attach it to a 1 1/2" pvc which is nearly 2" outside diameter)

Does this product require a tubing insert and a ferrule for the compression fitting? Else, what keeps it from leaking?

Does this come with an adhesive foam gasket to stick on the inner part of the plastic semicircle?

What is the width of the actual part? I am needing a more narrow piece than the one included with my unit.