VTA?

Obsessing is an obsession. The beauty of analog is if it sounds good then it is good 👍

For a technical starting point, you’ve done well by verifying VTF & overhang. To add - the top of the cartridge should be parallel to the record surface. I describe it so because many tonearm tubes are NOT on the same plane as their headshell. 
Any change of parameters from your starting point may or may not have a perceived benefit through your system. You be the judge.

A recent Ortofon webinar covered VTA a little bit, and noted that if you can't move your tonearm up/down then another option is to increase/decrease the tracking force by a slight amount, in order to affect VTA.

Which is true, but bad. 

Its true because increased VTF pushes the cartridge down more, the cantilever pivots up, and this does indeed change VTA. But its bad because, well first you have to understand why VTF is what it is in the first place. Its not to reduce stylus wear. Its to ensure the coils or magnets are properly aligned within the magnets or coils. VTF is a range because the maker knows suspension compliance and exactly how much force will result in this crucial alignment. 

That is why turntable setup is such an iterative process. First set VTF. Then VTA. But changing VTA changed the situation so you get to go back and tweak VTF again. Doesn't need to be endless, doesn't even need to be done more than once. Just need to know that's how it works. How far you take it, that part is all on you.

@millercarbon,

Tweaking the cart/arm/tt set-up is a completely different use of the term "tweaks" that is more commonly associated with the add-ons mentioned in your last sentence which is what I was referring to and I think most here knew that.