I recently switched to a half barrel for a boil kettle and have been struggling to hit my post volume target. If I collect 6 1/2 galons pre I am boiling off more than I use to. I get I need to collect more pre boil so do I just sparge with more water? What other adjustments should I make. Also when I mash I end up with close to 50% absorbed by the grain is this normal? I am trying to get more consistant with my brewing and this has been a struggle.