VinylPlayer

No it is so-so. But you are equipped with ears.
Take a good recoding with your favourite music that has little base.
This is good training also and cost nothing to get better sound.
1. Put your speakers approx 1m from the wall. Listen to the base notes. They should be thin but distinct and fast but Less hefty.
2. Move your speakers as close to the wall as possible. Now there should be a lot more base then before. But it is now not so defined and muddy.
Here you can go back and forth between 1 and 2 above. To learn and hear the difference and what to listen for.
3. Start at the wall and make sessions there you pull out the speakers from the wall more into the room bit by bit. Now when you know what to listen for you will hear muddiness disappear and more controlled base notes for every bit you take the speakers out from the wall. 
But at a point you feal that to much base information has disappeared. Then it is time to move them back a bit closer to the wall and you are close to fine-tune the distance!
 
Congratulations you have now a distance that applies to your preferences and type of music with your ears! 
 
So 200 mm is for those that do not care and do not know why and what the distance is affecting. You want as much SQ you can get from your hard earned money.

Not my first language..

recently updated my phone situation to an iPhone 8 Plus.  Which, of course, comes with the opportunity to dive into the world of portable headphone amp/dacs.
 
Ended up picking up a refurb Oppo HA-2SE.  It's kind of overkill for me but I liked the features and it does sound good in addition to being a beautiful piece of gear that is oddly satisfying to hold in your hand.
 

Needle Doctor is sending me out a new stylus, so hopefully it's good.

I read all of it. I don't know why, but I did. 

Another way to attack the problem is to vibration isolation the speakers against the floor. (If no vibration from the speakers find its way to the TT then that problem solved) 
 
Of course you still can vibration isolate the TT..
 
By taking out the vibrations at the source as the speakers generate them have also more benefits. Like that less distorted base sound travel in your build construction. Some say that the speakers also sounds better when they are vibration isolate from it's suroundings...
 
In other words do not just stare at the TT. The vibrations are coming from somewhere and maybe you need to fix the source..
 
Inspiration:
A intuitive video..

Yeah - It's not ideal but after spending a few grand on my TT and cart I need to slow my spending down.  It seems like a good balance for the time being.