In the second picture - of the guy holding his hand in a "V" - the mirror needs to be pointing toward an imaginary point directly between the sun and the plane -- not toward the plane itself.

Of course the idea is to flash the hand because you simply can't see the flash on the plane itself.

It is critical to have the mirror as close to the eye as possible, line the hand's "V" up with the plane (so the mirror/eye, the "V", and the plane are in a straight line), and then angle the mirror toward that imaginary point between the sun & plane until the flash hits the hand's "V". If the mirror is very close to the eye, then the flash on the hand should also flash the plane.

I don't think the artist really understood how it all works.

BTW, I've never really been comfortable at using the aiming grid on signal mirrors. I find my eye glasses keep the mirror too far from my eye and I really struggle to get the "flash" on the grid. I find the "V" method much much easier.