Upgrading State Circulating Quarter Set

My vote is that you leave the Set you already have almost completed in the album that it's in.

Here's what I did...and it has satisfied "me".

I put the "circulation" finds into folders. (zero value anyway).
Then I spent an immeasurable amount of time "upgrading" them all (both P's & D's), to get as close to BU as I could.
Once those folders were complete and upgraded to my satisfaction, I considered them "finished".

But the most important State Quarter collection for me, would be my Dansco with Proofs album.
For a quality coin filled album, viewing both sides is a MUST, I felt.
Only prime Uncirculated-gem-BU examples (from Sets) would do for this album. And then of course the beautiful Proofs and Silver Proofs in addition to these, make just a breathtaking album.....
I'm missing a few of the Silver Proofs still......but about 90% complete.

(I also did the same thing for the Territory Qtrs., too)

One can get "satisfaction" from completing ANY Set from circulation, or otherwise.
But you hit the nail right on the head when you mentioned "chasing shadows" about "upgrading"
Wow ! I spent SOOOO MANY hours pouring over quarters trying to get a better quality example to put in there !
And there always seem to be that handful of very elusive ones too !
But yeah, you just have to get to a "self" satisfied point with a "circulation" built album, otherwise upgrading could NEVER end !

And so the ultimate Set I decided to build, would have to come from breaking apart U.S. Mint, Proof, and Silver Proof Sets. Oh that was so much fun !
And I needed all the other coins contained therein to build my Cents, Nickels, Dimes, Halves, and Dollar Sets in this way too. SO it worked out GREAT ! ...

But NOBODY can decide or define "happy, content n' satisfied" but Y.O.U. !!