What type of power supply do Gridseed G-Blade need?
Either solution will work fine. For reference, check out these two setups:

https://www.youtube.com/watch?v=nCjSQMsdlKg

https://www.youtube.com/watch?v=2QrkWR5HdcQ

The former video illustrates use of AC adapters and the latter illustrates use of an external PSU.