You need to be wearing a good respirator (I use 3M, but several good P100 ones out there), not just a dust mask. Especially as you describe the fine...
I used a corded blower for years and the cord was a real PITA. I'd prefer a cordless blower that was inferior to a corded just because I hate having...
The innards of a 15A & 20A receptacle of the same grade device is identical, only difference is the face of the device, unless a 20A device is needed...