Feel Silly Asking This Question Alignment Parameters

@lewm I should have been more specific. Twisting the cartridge just a few degrees in the headshell is enough to blur the image. There are always unequal forces on the cantilever. A few degrees one way or another is not going to matter. Shoot, there are people who will swear their cartridge sounds better without antiskating and if you look at their cantilever it is skewed 5 or 6 degrees towards the right channel. 

@macg19 , I study every cartridge I can under high magnification. You can see some pictures here, https://imgur.com/gallery/stylus-photomicrographs-hmTaO0m

I check SRA and Zenith and the best cartridges are beautifully constructed. Azimuth is easy to see on the SmarTractor, you look for a symmetrical reflection and SRA is right when your arm is parallel to the record surface. If a cartridge is off it is usually easy to see. The last defect I even picked up with the naked eye. a cartridge with a SRA of 89 degrees. The manufacturer replaced it immediately. He had just started using a new adhesive and it was not setting up as fast and the stylus was drifting forward. I have yet to see a cartridge with a significant zenith error. I'm sure they are out there. I just got a Shure V 15 V MR body and ordered a Jico SAS/B for it. It will be interesting to see how accurate it is. I will post pictures of it.

@mijostyn I think you are talking about hearing errors in alignment which I totally agree are easily audible versus differences in the geometry you choose to align to.

But I am curious about your statement about "twisting the cartridge in the headshell a few degrees", by which I think you mean the zenith adjustment.  I have yet to find any information about how you can tell in which direction and by how much your zenith is in error.  Most of us simply align the cantilever since we have no way of aligning the diamond but as @macg19 points out and JR at Wally Tools has asserted the zenith error in how the stylus is mounted to the cantilever can significantly exceed the generally small errors that occur when carefully mounting the cartridge to the tonearm. 

Other than randomly twisting the cartridge back and forth and listening is there any way know in what direction and by how much the zenith error (including the error in the stylus mounted to the cantilever) is?  And I mean without paying Wally Tools $500 for their cartridge analysis service.

@neonknight : I don’t know from where have you those overhang distances in the OP because the normal calculation for that P2S distance puts you almost there and at the end is that with the calculated Löfgren A overhang you have not any trouble with the null points:

Tonearm Alignment Calculator Pro - Vinyl Engine

"  its a matter of wanting to get this set up optimized. "

There are several ways to optimize a tonearm/cartridge alignment set up at the one with lower traking distotion/error is the SAT tonearm alignment that any one can use.

R.

Dear @mijostyn : " I prefer Lofgren B. Lofgren B generates less distortion...."

For many years my way of thinking was exactly yours till you fall in count that those tiny differences ( we can see in all those VE links I posted. ) and everything the same no one including a bat can distinguis in between no matter what and the best trade-offs per sé is Löfgren A.Everything the same how can you detect a difference in tracking distotion between Löfgren A and B when the measured groove to groove at each mm. change at lower than 0.01%? Changes is so tiny that we accustom to thozse changes with out detect that tiny changes.

Makes sense to you? because all of us have big imagination.

R.

@neonknight : " This document is reproduced here by kind agreement of Mark Baker at Origin Live. "

" Rega arms and Origin Live arms require mounting dimensions such that the centre of the platter to the centre of arm hole is approx 223mm plus or minus 2mm tolerance and the hole diameter for the arm is 24mm to 25mm. "

At P2S 225 distance L¨fgren B gives you 17.53 that has no consequwences in your 17.5 desired overhang.

Cartridge 2 Point Alignment Protractor (originlive.com)

You can read OL uses Löfgren A. I gave you the calculations for in one of the links.

In the other side it's easy to ask OL which kind of advantages gives its alignment against other normal alignments, I think you need to know and evaluate if is what you need or could not makes a differences.

R.