keif?

from an oz of good bud how much keif can you get out of it?

I've gotten as much as a gram of kif per every 3.5 grams. That was with some Full Melt Madness. I'm pretty sure it was outdoor too.
However on average a half gram to 3/4 of a gram per eighth is a pretty good yield. So for an O', that would be about 4-5 grams.