Step 6 of the printed instructions included with my aeropress state 'fill to 2'. I see that the downloaded version states 'fill to 1'. Which is correct? Electric kettles are hard to find here in Italy, let alone ones with temperature control. Waiting 17 minutes is not a realistic option, nor is measurement. Any other suggestions for achieving optimum water temperature, please? – From Mike S.

[In response to your first question] Either is ok.
Put a dial thermometer shaft in your kettle. Either through the spout, or through a small hole that you drill in the top. When the kettle starts "ticking" watch the thermometer and stop heating when it nears 80C.