Very cool! Thanks for sharing. Just got my first Arduino last week, and didn't even think about using it for brewing.
How will you clean the flow meter?
Cheers and happy coding.
Go by the taste. If the tradeoff is between no secondary and too much headroom in secondary, I would go with the latter. I have gotten funny tastes before from leaving beer on the lees too long. Just see what happens -- I bet it will be fine.
you're probably fine. it might take a little longer to start. the only time i have had trouble with yeast is when i pitched it with wort too hot. then i just added more and it turned out fine.