Thoughts on VTA......

Two things you can't cheat with vinyl play.

1) Physics and 2) the Record Pressing Plants.

PHYSICS (the obvious one)

Raise VTA ....you lower VTF and alter other set up parameters.
Lower VTA....you raise VTF and alter other setup parameters.

RECORD PROCESSING PLANTS. (not so obvious)

There were / are no standards for the vertical angles the records are cut at (the included angle).
American plants angles are different from European plants.
Each time the cutting stylus is replaced (every 10 hours?) the new one goes in a little different than before. 8^0

********************
What to do ?
********************

If with one average setting your vinyl rig does not allow you to hear these differences, or it does not bother you too much.... consider yourself BLESSED ...enjoy your records.

If however you hear differences even with same thickness records (different included angles) ....and...maybe..... suffer from a little Audiophilia Nervosa...... there are at least four things you can do from my personal experiences over the years. 
  
1) make the necessary adjustments after VTA changes.

2) acquire a preamp with adjustable on the fly "Gain". Lower gain for bright records and vice versa.
  
3) acquire an amp that allows for on the fly gain changes.

4) acquire a tonearm that was designed with VTA changes in mind and allows you to make these VTA changes, with ease, and not affect any other setup prarameters. FWIW - One tonearm only - exists - that I am aware of that has this capability. ET 2.0, and ET 2.5. They are protected by patent.

If there is another tonearm let me know.  

Cheers

Enjoy your records.

I used to do it by ear then I got a micro meter on the fly mod for my12" Jelco and well now I wonder how I managed with out. makes it much easier and faster IMO, same results in the end. as for changing for thickness I really can’t tell the difference in that small of a change, with a 12" arm anyway. that’s on a VDH cut tip as well.

I'd like to see the math on the stylus angles change vs thickness changes of records be it 180 ect. 9"-10" 12" go. 

I set my arm level and lowered  it until I got the perfect tight bass I was looking for.. took me 2 hours my first time! Lol 

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.