Dritz Quilting Hexagon Paper Piecing (100 Pack), 1.5"

is the paper heavy duty?

Can you leave the paper in the blocks or must it be removed?

Are these for sure 1.5" along each side of the hexie (3" from point to point)? Just want to make sure I choose the right size.

How is this measured? Is it 2" along one side of the hexagon, or 2" in diameter across the hexagon? I'd like to use up some spare jelly roll strips.