In the past few weeks, I have tried almost every conceivable plate arrangement I can think of or of which interested me from Internet videos.
My conclusion? Direct hard wired plates and series cells with natural plates both work equally well, it is just the series cell needs more NaOH (lye.)
Plate size and type? Business card size, thick enough to hold the flat shape from one cell to another. I used .0062 316-L. Number of cells? One cell per one point five to two volts seems to be the key.
Yes the neutral plates cuts down on the amps. It also cuts down on the hydrogen production. To boost the hydrogen production you need to boost the NaOH several fold which brings up the amps. Amps for amps, everything else being equal, I see no discernable difference in my bench tests. With the hard wired plates, you get the benefits of less NaOH to activate your distilled water to make the gases of electrolysis.