I found some notes I made.
My original description of the adjuster as parallel to the pushrod may be true, but it's not significant.

The shape in question is a right triangle. The geo:
The adjuster thread is 90 degrees to the pushrod lever, a horizontal line equal to the lever's length (the triangle height).
The exposed thread is a vertical line descending from the left edge of this line, the height is the difference (the triangle base) in adjuster positions.
Draw the hypotenuse. It's longer than the 1st line. In any right triangle the hypotenuse is always the longest distance.
Therefore, the pushrod lever becomes longer as the thread length increases.
The valve lever length is unchanged, so the rocker arm ratio goes down.

If the pushrod lever (triangle height) is 1.00" (fairly common) and the valve lever is 1.70", the ratio is 1.7:1
If the exposed thread distance (triangle base) is increased by .100", the hypotenuse length is the square root of the sum of the squares of the 2 sides (Pythagoras).
1.00^2 + .100^2 = 1.01^.5
1.01^.5 = 1.005

The new ratio is 1.70" ÷ 1.005" = 1.691:1

If the adjuster angle is different, the math will be off, how much and in which direction? Give me the angle.