There's a lot of variables there? Pot size, medium,what you consider early vedge, strain etc.
Water them till you see some run off.
Yes on the piss too. This seems to be a tried and true organic method. But like I mentioned to someone else don't go take a leak In your hydro reservoir or anything. I only use piss outside in raised beds though
Dilute it. You can find the right ratios inn one of the threads on RIU. Peace