I hadn't played with the EQ settings in a while and opened it up just now to find that an update has added numeric values to the sliders, allowing them to be set accurately. This is great, thanks Andre! Looking through the changelog I assume this happened in build 839.
If anyone's interested, it looks like the Q value for the filters is 1.5. This is necessary info if you're looking to model the EQ in another app in order to match the response to a target curve. I measured this the same way as described above and found the effect of the 1kHz band was 3dB down at 1.3kHz