Thoughts on VTA......

My Triangle Art OSIRIS MK2 tonearm is fully adjustable including VTA. 

I think that obsessively fussing with things like VTA for each record is one of the reasons I now mostly listen to Tidal and only use my vinyl for select music. In other words, after a while I noticed I was fiddling more with the rig and listening less to the music.

OP:
"I have read countless posts where members are spending hours on exacting setup of their VTA with varying levels of tools.

Then there is another camp who set by ear.

My thoughts/questions on this subject arise from vinyl thickness difference.

Surely going from a flimsy flier early 70,s vinyl to a later 180 or even 200gm issue is going to change that painstakingly set VTA considerably.

So thoughts rattling round is why go to all that trouble when it IS going to change depending on the vinyl played?

To my mind it would appear that one of the arms that includes on the fly VTA adjustment would be the answer.

Your opinions or suggestions?"

MF has some good comments on this in turntable setup videos you can find on YouTube. 

In my case, I learned what effect VTA has on sound when setting up my first Benz Glider. I kept lowering and lowering, it kept sounding better and better..... until it didn't. I went back up a little. Better. Went up and down in smaller and smaller increments until I was satisfied. This was with the Graham arm. "Small" increments came down to interpolating within the smallest marks on the Graham adjuster. The width of one of his marking lines, if I remember correctly. Seemed crazy at first, but I kept at it until I was sure. The most time was spent not adjusting, but confirming what was in hindsight pretty obvious from the start.

Years later I went through this same process with my Origin Live Conqueror arm and Ruby H. Then again last week with my Koetsu. I can zero in really fast now but its always the same deal, the tweaks between records are really tiny fractions of a turn.

Now if you do the math, threads per inch, fractions of a turn, its clear VTA adjustments of much less than a hundredth of an inch are audible. That's why VTA absolutely must be set by ear. 

Unless, of course, the difference either does not matter to you or you can't hear it. In that case then, why bother?

In my case, it takes me nearly no time at all to tweak VTA and write it down. One album side, couple tweaks, max. Write it down. One and done.

Even then there are still times when I put one on and it sounds so good I just enjoy it, no tweaks. In that case I just write down whatever VTA was. So I can repeat it. And that's that. Because for me that is the whole point, to enjoy the music. Whether or not someone else can appreciate it, or how much time they spend tweaking, simply is not a factor.

On a 9” arm you need to raise or lower the arm pivot point by 4mm to change SRA by 1 degree. 
Mike Fremer says he sets his with an average record and leaves it alone since the thickness variance causes changes in small fractions of a degree.

Why not just use platter mattes with different thicknesses? I have several I’ve cobbled together. Seems to work fine for me.