Andrew
Part of the answer you require was covered by Arenaclean - the scoop in the tub is 1oz or 30ml. It doesnt say so, not on my scoop, but I have tested it with the knowledge 1oz is 30ml by using a scoop marked 15ml and putting 2 of those scoops of powder into the scoop I got with my DFC210. 2 x 15ml fits nicely- not heaped though.
The 2nd part of your question I covered earlier - you will need 8 30ml(or 1oz) scoops per litre of water - does go a long way though - dont linger with the spraying, keep moving. You can spray a room in no time at all.