3 questions if I may, then details below.
1. Do you you often see a krausen (or the remains of krausen, if you've missed it overnight) in any of the steps of a bottle harvest? I haven't in my first two attempts so far: see below.
2. Do your bottle harvest starters taste just the same, with as little sourness, as when you make starters from a lab vial? Mine haven't, yet. I do not decant between steps, if that affects things there.
3. Is it possible that my second 250ml step, currently on the go, has finished it's growth phase and started to clear a little within 9 hours?
I currently have 250ml of ~1.030 on the go, stepped up from 50ml of 1.020 added to the last 1cm of a bottle of St Austell Proper Job. I saw nothing in the 1st step apart from sustained turbidity for the first day or so followed by accelerated clearing. Last night I proceeded to this second step regardless. I noticed a little sourness in the residue of the fist step afterwards.
Only 9 hours later I have a jar with a good layer of trub/yeast settled and the beer starting to clear at the top. A swish around reveals noticeable off gassing. There's no sign of krausen marks.
This is my third attempt to culture up some commercial bottle yeast. The first was an ~8% Belgian of unknown age; failed - it got infected in an obvious way before it got going. I think my first step was too heavy in any case. The second was from the dregs of 3 bottles of a local brewery which I know to be the primary yeast, which got going well through the steps and plenty of yeast was visible in the final 1 litre stage, but there was just a little too much sourness in the taste for me to pitch it. It looked fine.