Simple question re pos ground wiring

[m7b52000]

I understand pos ground PNP fuzzes and have built a few battery only versions. I am now building one for use with my Voodoo Labs 4x4 power supply which apparently has isolated outputs. If this is indeed the case should I:
1) wire the fuzz up as per usual with power rail connected to long lug of DC jack and
2) use a polarity inverting cable DC cable fro the power supply

or is 2 unnecessary if I am using a single truly isolated output from the power supply. My feeling is that 2 IS necessary.

cheers,

Tony

[m7b52000]

Upon reflection all I need to do is reverse the polarity inside the pedal then use an ordinary Boss type centre neg cable?