Why do I need neutral plates in my hho dry cell ?
Are you going to get the same amount of gas production from a +-+- configuration as you would from a +NN- or +NNN-NNN+ given the voltage and amperage remains the same?
Extra neutral plates will divide voltage, with 2.33v per cell being the best. You will probably not see much difference in production between the two setups you mention.
The big difference will be the temperature of the cell after some run time. My suggestion would be to try the two configurations again and use a watch to take temp measurements at set intervals, naturally starting at the same temp. This should show you the true power of neutrals.
You will find +NNNN- will be best, and after hundreds of experiments that is exactly why we use this configuration on our COMPLETE HHO DRYCELL SYSTEMS