Maybe this will be helpful, maybe not, but thought I'd post about my experiment anyway:
I have a restoration battery that's weak - prior owner let it run low on water, plates exposed - and after it sits, reads just over 11 V.
Figured I'd see if that desulfation gizmo in the MA article would work.
Charged it back up from 11.3 - 12.6 is as good as it gets - and then connected the gizmo per instructions.
Back & forth between the gizmo and the charger, seems to be gaining .1 - .2 V per day when I test it after it's sat for a while.
After it sits overnight, it'll read 11.6 with the voltage tester, which is accurate on other batteries & charging systems.
So far, I'm 5 days into this; maybe the battery's too damaged, but I'll play the game for another week or so.
Between the gizmo instructions and the article, seems it could take a couple days to a month.

Kinda hoping to avoid the mess of gutting the battery for the hidden-upgrade deal, but we'll see how it plays out.