VTA my compromise in setting

I use a shim mat (placed underneath my main mat) for thinner LP's (VTA is a PITA to adjust on my old SME).

You might look into a mat (that you like the sound of) which comes in various thicknesses.

I do have "some" very thick LP's from the 50's, but I usually just use the main mat (a bit fatter bass/softer treble) as I don't have that many.

DeKay

My Grado cartridge is quite sensitive to slight variations in VTA.

Prior to Grado (started using Grado 20 years ago) slight VTA variations were not an issue with the Sure V15 III's I used from the mid 70's thru 1986.

Decks have all been Thorens/SME combos with the exception of a stock TD165 that I purchased to experiment with (most of the popular online mods of 20 years ago were tried).

My most used shim "mat" is a thin/floppy Fripp and Eno import LP that I purchased around 1977/78.

It incurred a bad scratch early on but for some reason (?) I hung onto it.

As an experiment try a thin LP as a "shim" mat to see what it does.

DeKay

Setting it for the "mean" of your LP library would make sense, but if you do not hear a difference between 145/180 I can't imagine how you would go about it.

Maybe just forget about it for now and if you come across a thin LP that's sounds "thin" try replaying it with a shim mat.

I'm on my 3rd/last DIY rice paper/cork spot mat as I no longer have enough material left to make #4. 

Dreading looking for a replacement, though I do know that I do not care for squishy and/or ribbed rubber (like the OEM) in my setup - which narrows it down a tad.

DeKay

I set VTA to what the major majority of my 2000, or so, LP's are thickness wise (I don't know the weight).

My SME 3009 II non-improved is not completely level to the platter, but it's close and sounds fine.

As mentioned, I never experienced sound differences with slight VTA variations until I started using Grado.

I have Silver and Gold Grado Prestige bodies and the removable OEM styli appear to be the same.

The Silver and Gold sound the same to me, though the Gold had a higher retail price.

My main speakers are vintage 8" wide band single drivers (Stephens Trusonic 80FR and Elac S-517), so I'm missing response below 50Hz and above 10K-11K Hz.

Your cartridge seems to be fine with slight variations in VTA as were the Sure V15 III's I used for years.

DeKay