1. Already answered many times
2. For me it depends on how high i wanna get. I can be good with just .5g ill do more if i wanna get stoned though. And either way ill probably load it up again soon. I also try to corner it though when smoking with others esp after i add a bit if kief to the top.
3. I'll usually wait until i really start coming back down from my peak. Probably about 3-6 times it really varies or until i get tired. Also depends on how much i have