ALEMBICS can have a very low action IF your playing style allows it. It REQUIRES a lighter touch: You can't expect to lower the action to where you can barely get a cigarette paper between the string and fret, then go out and bash away with a heavy pick and complain that it buzzes.
As a practical matter, I think they can go lower action more easily because of the wonderful adjutable nut. Virtually any other bass would require you to file a litlle deeper, a little deeper, which is a tricky proposition if you're trying to get that last little fraction of an inch. On your SC, you just turn the allen screws in the nut: If you go past, just raise it back up. This is a WONDERFUL luxury.
This is why I say that ALEMBICs are the BEST instruments on which to teach yourself how to adjust your bass. The combination of the adjustable nut, the double truss rods, and the curved bridge with only two height adjustments (instead of each saddle separately)and the neck thru make for a very controllable package of variables. On a PBass for instance, you'd have a plastic nut, you'd adjust each saddle separately, and more likely than not, you'd at least have to pull the pickguard, and probably
unbolt the neck to get at the truss rod FOR EVERY ADJUSTMENT (plus, did you get the exact SAME neck set angle when you re-bolt it to the body?). It's no wonder very few bolt neck guys ever learn much about adjustment. I wouldn't go through all that, either.
If it were me, I'd raise the bass side of the nut just SLIGHTLY and see if it goes away; I'd bet it will. Keith graciously posted a link to some of my setup posts, hope they help.
Congratulations on a beautiful SC.
Best Wishes
J o e y