What angle should I set the VTA on my VPI turntable?

Hshifi is conflating SRA (~92 degrees) with VTA (~21-23 degrees). The two are interdependent of course.

Mijo, an analysis of data in the form of photos posted on vinyl asylum (I think) revealed that most “amateurs” draw the lines incorrectly when adjusting SRA with a USB camera. Thus they arrive at incorrect SRA. Personally I take it as the height of anal audiophilia even to try it. But that’s just me.

Some time ago, this issue was discussed here.  The question then was not "whether" VTF goes up when the pivot point is raised, but "how much" does it go up.  Someone did the experiment, and the answer was "not very much", but definitely VTF went UP.  You could repeat the experiment but don't start with VTF =0 as in your model.  Start with a real world situation where VTF is any value >0.  Then you will see VTF go up if pivot is raised.
Also, think of your car sitting on level ground.  It has a given weight distribution between front vs rear wheels.  Think of the front wheel pair as the stylus tip.  Now jack up the rear of the car.  What has happened to the weight distribution?  More of the weight is supported by the front wheels.

Let me be sure I understand what you are saying, Lutke. You say to place the cartridge on the LP surface at zero VTF, first of all. Correct? Typically when VTF = 0, the cartridge is floating in space above the LP surface, and the tonearm is parallel to the LP surface, else the tonearm is not truly balanced. OK, so in order to get the stylus to come into contact with the LP, I am going to have to crank down the VTA adjuster/pivot point quite a bit from where it would be for normal use, i.e., to play a record. So now I have got that done.  VTF = 0, with the LP in contact with the stylus tip. Now you say to crank down the pivot point still further. Yes, that will increase VTF from zero, because the LP must exert a force on the stylus tip to push it and the tonearm upwards; now the tonearm sits at an angle, with the cartridge up and the counter-weight down. The "VTF" you are measuring is that force needed to perturb the tonearm from its natural position of parallel to the LP surface, when VTF =0. Anyway, any time you want to move a sofa, I am your man. You can be on the bottom as we go up some stairways.

Your model is flawed.

Dear lutke, I don’t know about your model, but throw it out. Now think that you and a friend are carrying a sofa. On level ground, the burden is equally shared. Now you have to carry the sofa up a staircase. Who is working harder? The guy at the top end or the guy at the bottom end? Raising the pivot point shifts the center of gravity toward the stylus. VTF goes up.

But if you replace VTA with VTF in cleeds post, the statement is correct, tail up, VTF up.

9 out of 10 of us wouldn’t be able to measure SRA accurately even with a USB microscope. For most of us that method would be a waste of time and money, unless maybe one has been trained by an experienced person, like MF or Peter L. This has been shown more than once on various vinyl forums. IMO, the best advice is to set the top of the headshell parallel to the LP surface, then go up or down from there if the initial setting does not yield good tonal balance. As many others have already written.