Octal works a little better than hex when you actually have to toggle in a boot loader at the front panel, IMO. I think 8 switches are a little easier to manage than 16 for this use case.
used to know the pdp11-05 bootstrap by heart .... I'm not sure it matters - I can imagine that 2 lots of 2x4 can be done with 2 hands in 2 operations would probably be faster ... but it's kind of moot because the front panel was marked in octal so that's the way one learned it
I think that standardising on 8-bit bytes and power of 2 words is what pushed us to hex as a standard notation
