LP Thickness/Taper

I find your picture interesting in that the outer rim is not resting on the turntable platter. Since the rim and center are considerably thicker to suspend the playing surface off of the platter. And I would imagine that the 180 gram pressings have different relative thickness between the outer grooves versus center playing area.

My guess is that the pressing process plays an important part as the puck is pressed from the center out as pressure is applied. Maybe the bulk or mass of the puck causes a restriction equalization of pressure across the diameter. Although I would also think that the manufacturer of the press would have accounted for this after all these years of vinyl manufacturer. It would be interesting to run this same experiment on records based on the manufacturer of each pressing machine. 
Kudos to you for taking time to do this, but although I don’t see that your motive is my curiosity, but I find it intriguing none the less.

However if I interpret your motive or question. I don’t know how a tonearm setting can be set to anticipate and compensate for this variance. Once again I am reminded of an article which I think Michael Fremer wrote about the playback of vinyl contradicts logic on many planes. But thankfully it does it as well as it does.

thank you for this food for thought 

@theo 

I find your picture interesting in that the outer rim is not resting on the turntable platter.

Many turntable platters are designed like that because the outer rim of the record is much thicker than the grooved portion.  By hanging the thicker, outer portion off the platter, better contact between the record and platter is made.  That's an old Goldmund Relief Mat. It looks like they chose the perfect diameter as the LP begins to get thicker right at the edge of the mat.  In fact, the entire mat fits the LP like a glove.  It perfectly matches the contour.  It even matches the stepped portion of the label area.  It's more apparent when the image is viewed full size.

However if I interpret your motive or question. I don’t know how a tonearm setting can be set to anticipate and compensate for this variance.

Any arm with adjustable azimuth will be able to compensate.  You just need to figure out a way to adjust azimuth while taking that 0.12 degrees into account.  I've figured out a way to do exactly that and will be testing soon.

I always check azimuth in the middle of a thrift store record. And several 1/1000ths of an inch matters not! Not in the real world!!

I always set all cart adjustments with it aligned exactly half way in the middle of the record. On my VPI Classic TT it specially matters for VTF and anti skate. But it would also be beneficial for azimuth if all records are built like the one you tested, which I doubt. Anyway, to test a cart alignment either at the beginning or at the end of a record makes no sense at all. Always test the middle for the best average adjustments. 

Since the angle of incline appears to be constant from outer to inner grooves, seems to me if you set azimuth correctly at any point on the LP surface, there would be no problem related to a changing azimuth angle.