1. I put mine in and let it sit for 24 hrs
2. I leave mine in the secondary. I think provides a more uniform aging.
( I have some aging for 4 years now that I'm getting ready to tap into)
3. Experiment and find what you like. I like SO 4 for cider
"Your HYDROMETER is the only BEST indicator of fermentation activity. Nothing else is accurate or consistent"...Revvy