Sources I have at hand that say point the incident meter at the camera from the subject position (or along a parallel axis in the same light):

Gossen, Sekonic, and Minolta incident meter instructions, i.e. the people who design and manufacture the meters. (They also say to use a flat disc for metering lighting ratios while pointed at the light, but the dome pointed at the camera for the full exposure reading for 3D objects. And use the flat disc for photographing flat art.)

Six well-known and well-respected photography manuals: Vestal, Adams, Davis, London & Upton, Horenstein, and the Leica Manual.

So that's about nine for 'point at the camera'. As I said earlier, all the dozen or so studios I worked in pointed at the camera when metering for the exposure. (At the light source for measuring lighting ratios.)

Sources (besides Collins and acolytes on the internet) that I have seen that say always point the meter at the light:

Zero.

The dome of an incident meter is a 'model' of a 3D subject. The reason it's pointed at the camera is so that it simulates the 180 degree portion of the subject that the camera can see, thereby reading the light incident on what the camera can see. If you point the meter off the axis toward the camera, you're metering stuff the camera can't see. Going off axis a little bit doesn't often change the reading enough for you to notice on film.

There are obviously times when metering with an incident meter won't work well this way. Say I had a backlit white scrim with no source of light on the camera side. I wouldn't get a proper exposure for the scrim if I incident metered from the camera side with the dome pointed at the camera. Both incident and reflected meters need an operative brain to get consistently proper exposures.

As always, you're free to use your equipment in any way you want. But it does pay in the long run to understand its design. As the unix guys say, RTFM.

Lee

P.S. It's apparent that a member of my very short ignore list is now in this thread, so this is my last post here since I'm not reading everything.