Good to know Edwin- thanks for that information.  I was actually thinking of emailing Mica and asking her as I think I'll be ready to start looking for a used Series I around the New Year.  If I get my hands on one, I'd be interested in doing the swap.

One of the Mods might want to consider adding David's post (from the 1st link) to the Must Read section regarding the master volume + pan vs dual volume controls.  I think I finally understand the issues after reading his explanation.

Jazzy,  
 
I have a master volume on one of my basses and I absolutely love it. The value of setting up the sounds you're looking for between the neck and bridge is the the first thing I seek, and the master volume, is the last step, before taking sail.  
 
For me, the master volume, is like the rutter on a great ship, that points me in the right direction.
 
I am more than likely, be adding a master volume on my 76 shorty one of these days; along with serving or replacing my existing pots.
 
Peace and Love,
 
Hal-

Hal, I like your rutter  analogy  .
I like the master volume on my  SII as well.

I just had to smile re-reading this old thread in the times before I had a series bass. I wasn't in a position to try out a series bass before buying one and it is well documented on the forum my series journey. The first time I played one was when my series II Europa 5 string was handed to me by Mica at the factory in 2012. It was when I took it to the alembic gathering and put it in the hands of experienced series players that I could hear for myself what the bass was capable of achieving sound wise. I have bought a short scale series I since then so I absolutely get the sound of the series bass having owned a signature bass since 2002. That said, the signature bass still has a sound I want to use and I recently modified it to anniversary electronics, mainly because I use the series basses mostly now and it made sense to have the same control layout on my main gigging basses. It also makes sense to have a master volume on a series bass too so I may look at that if/when it becomes available as an after build upgrade kit. But for now I can use what comes standard.
Thanks to you all for your input to my query and having read the thread again my title should not have been stated in a competitive manner as in reality I was eventually going to end up with both. :-)