you need to figure out your own boil off rate. It depends on BTU, kettle dimensions, shape, etc. On my Blichmann burner, I am typically about 1G/60 minutes at a moderate boil
Absolutely not, in fact this is a great way to explore the gazillion new hop varietals out there. If you can do it easily (like if you have a valve on your kettle), it may help to heat the ENTIRE wort volume to around 180 to make sure you kill the majority of stuff that can be growing before you start splitting the batch.
I'm not that well-versed in water manipulation, but from what I understand, Kai's sheet was the gold standard before Brungard trumped it!
Thanks Again. BTW if any newbies are looking to brew a Natural Lite 3.2 ABV clone, the recipe I posted beats it in flavor hands down.
Here's my prior endorsement of BIAB.