I used a simple "charger doctor" from Adafruit
Oh, interesting! I hadn't seen this product before. I see they also have this, which would allow you to connect it to a (probably more precise) multimeter: https://www.adafruit.com/products/1456
I run my Pi 2 headless and I find it's using about 280mA - 320mA under a reasonably normal load.
It's possible that the adapter I was using was a bit dodgy, too -- I really should take some actual measurements to confirm.