Apologies, I originally missed out the quite pertinent 2 / Two part of the name, when referring to the Voodoo Lab Pedal Power 2 Plus / PP2+. I've now edited both the title and OP to correct this error.
Also I've done some further research and found that all the information about using a 300mA power supply in the B2 manual, also applies to several other similar products from this line. Those include the Zoom B1, B1x, G2, G1, G1x and potentially other units such as acoustic guitar multi fx pedal within the same family.
To clarify, I'm seeking to find out if my Zoom B2 actually requires the 300mA power supply, as per the specific Zoom product referenced in the manual, or whether these units can run on slightly less?
The power supply I'm hoping to use is a Voodoo Lab Pedal Power 2 Plus, which offers two higher amperage outlets rated at 250mA each. I understand I could use an amperage doubler to provide 500mA from both of those outlets, however I also have another power-hungry digital pedal that will need the other 250mA supply on the PP2+.