My first Alembic was an Elan-plus (Europa electonics).
And I love the Europa electronics. I think they are equaled by the Signature electronics and surpassed only by the Series.
When I commissioned my custom, I most certainly used my experience with my Elan as a frame of reference. I wanted more versatility than the stark 2 options of 0 Q or 8 db of Q;
I considered several options; the next closest option that I passed on was to have a 4 position Q switch (using the standard 4-position switches they've used for years... actually decades, I think.)
Bottom line: my custom has separate filters with variable Q controls and bass and treble dials and a quick-change boost-cut mid-range control for each pickup...
And each pickup has 2 toggles that allow me to choose between 0/4/8/12 dbs of Q.
This is close to perfect. Basically, I have 4 Q settings: no Q, a little Q, a moderate Q, a strong Q...
Most of the time, I use either the 4 or 8 db setting; I occaisionally use the 0 Q option; I rarely use the maximum. I actually like the incremental-ality of it... I like it as much as the CVQ.
I view my system as close to perfect. But if I got another custom, I WOULD use the current 4 position knob to choose between 3/6/9/12 dbs... I think -based on my experience- that this would be (at least for me) perfect, and that a CVQ would offer little more. I think this would be all one would need. A 1 db Q boost would be almost absurd; only the sharpest ears could distinguish it from no Q, just as 2 dbs of Q would be indistinguishable from 3. Going in increments of 3 would be the most I would ever need. The fact is that my current system now is extremely versatile and perfect for me. The 0/3/6/9/12 system would just me a very slight refinement.
My 2 toggles let me actually turn off my filter altogether. But, aside from this, the standard 4-position switch could easily give one the 4 options that I have (0/4/8/12 dbs)... and believe me, these options cover all the bases (no pun intended) and offer tremendous versatility -and consistency.