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

Funny, my experience is the opposite.  I wonder if the answer flip flops depending on which side of parallel the tonearm is.  Above, below or horizontal.  I know what my arm as it's set up does.  Physics isn't my thing and there could be (and most likely are) other explanations I've not considered.  I would love an answer from someone who actually knows.  No one here does, including me.  It's fun and didn't get too sideways.  Cheers!

Thanks guys.  If jcarr catches this thread, maybe he can weigh in with some practical advice since I am using one of his cartridges (Lyra Kleos).  

My sense is that lewm's approach makes the most sense.  I ordered a cheap super light/small bubble-level to double-check the azimuth and VTA one more time.  I will probably tweak the tuchus (the backside) of the arm up a smidge and call it a day.   

While I can envision that raising or lowering the tail of the tonearm will affect VTF and the P-S distance to some degree, I surmise that a small adjustment of the VTA wouldn't make all that much difference in SQ.  I am not OCD about my turntable and do not have the patience to make a minute adjustment to VTA and then readjust the P-S distance and VTF.     

Hello,
Not even close to an expert here. Here is my two cents. Please do a final VTA adjustment after about 50 hours or per Michael Fremer set it to 93* when the cart is new. As the cart breaks in or settles you will lose about 1*. I think the angle is 92.3*. After a lot of playing you will naturally get to this. Or set it to 92* at the beginning and recalibrate after 50 hours. Regardless once set up I would do a listening setup. That’s what I did when setting up the Prime with the unipivot arm. 

Hello,
One more thing. Please do not set up your table with a cheap bubble level unless you checked or calibrated it with a really good level. I have made this mistake and found out these cheap bubble levels are not true. Your albums and your cart are not cheap. Please do not wear your gear out sooner than it should. It has been proven that a well set up cart sounds better and makes your cart and records last longer. I’m not trying to get on my soapbox. This equipment is not cheap and some of these albums cannot be replaced. I hope this helped. 

Miller:   "...I lose interest in tweaking..."

SURELY NOT !!!!!