Bench leg cut

Height to underside

Leg angle

Black dot: where the two pencil lines cross. Red dot and line: the cut. Hatched: waste.

Measure down the inside edge from the black dot–

Cut line angle to the inside edge–

Saw setting (off square)–

Marking each leg

With a straightedge, pencil the underside of the seat and the inside edge of the leg past the curve until they cross. That crossing is the black dot.
From the dot, measure the red number down the inside edge and mark it.
From that mark, draw the cut line at the angle shown to the inside edge, right across to the outside edge. The taper doesn't matter; the line is set from the inside edge only.
Cut on the waste side of the line.

Check the angle on each leg. If one differs, enter its angle and mark that leg with its own numbers.