All the relevant numbers are in ratios between distances, meaning you don't need to change anything about the procedure if you're using the standard units of measurement.
True. It still thew me off having to estimate metric units from the imperial units and doing that estimation while reading an article about estimation.
The point is you didn't have to do that at all! It works for any unit of length. Bring your own units!
Miliradians aren’t metric. That’s hard for a lot of people to figure out.
1 banana at 1000 bananas away
I just tried it with a cup using cm and it works just fine. Whatever your estimate of length is is the same unit as your estimate for distance.
This seems like a fun thing to practice while I'm out, thanks.