Townshend Springs under Speakers

In that case Podiums first, for sure.

Thanks, MC! I’ll probably start then with the pods under the components. I’ve only had intermittent luck with my DIY rollerblocks, and I’m thinking that success with these devices is hostage to the weight/pull exerted by heavy power cords. Trying to neutralize cable pull with Furutech Booster clamps seemed to defeat the value of the rollerblocks and I began to suspect that it was best to use a very light touch with the Furutech clamps when paired with ball-bearing isolation. I take it that this might be less of an issue when using 4 Townshend Pods (as opposed to 3 rolllerblocks) but was also wondering if the "clamp" strategy of the Furutech Boosters was itself a dubious solution to cable vibration that needed to be addressed as well.

Just read your update:  podiums!

Podiums under speakers
pods under amplifier (s)
pods under pre amp
pods under Dac/streamer. 
That’s the order of improvement in my system 

The greatest improvement for me was Podiums under the speakers.  I then placed the pods under my tube pre amp replacing the HRS footers.  Speakers first in my opinion.

I agree with MC, that properly loaded and damped springs are likely to be the sonically best solution given your description of the structure you reside in.  
My situation is a bit different from most here in that I use individual springs under my speakers and subs,  instead of the Townshend or Nobsound products.  However, I went through quite a learning curve and much trial and error before finding the appropriately sized springs.  I figured out how to damp the springs, and it helps that all my speakers are supported on very stiff, solid, and heavy Sound Anchor stands.  In addition to removing the guesswork, the Townshend pods and podiums may be better damped and have the ability to be preloaded.