In bowl 2:
350g filtered water; less than the 375g specified because of the advice given in this thread.
75g of a very healthy, bubbly, lovely-smelling, beautifully risen KAF AP leaven which was poured off from my kept starter and fed at room temperature twice (1:2:2) a day each day for two days before beginning this recipe - and doubled in size.
The starter originated with the KAF kit. But I have been successfully feeding it for a couple of months with KAF organic All Purpose. Usually 1:1:1 twice a week with Britta-filtered water and plastic/silicone tools. Stored in fridge. Always looks and smells what I take to be just right.