Personally I'm more interested in knowing how much powder I have than how much water. (Though I'm not sure how accurate I can really be based on the volume markings - weight would be more accurate, but also a hassle.)
A small amount of water seems to work, though it does increase uncertainty in powder volume a bit.
I used a measuring cup (iirc 75ml) for the powder. My typical meal would be three cups of powder and 300ml water. It's quite thick that way, my friend used more water.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.