BIAB kettle volume/sparging question

[WildOnions]

I want to do a 3 gallon BIAB with a 5 gallon (20qt) pot. Ideally I'd like to do single pot, however I'm thinking I may not be able to make that work. Using Green bay rackers can I mash it calculator I'm showing about a max of 2.5 qt/lb with the 7 lbs of grain I am using to still fit in my kettle. That's 4.375 gallons, with grain absorption I figure I will be down in the 3.5 ish gallons range after the mash, though I plan on squeezing the bag so that could change that number.

I figure I want to end up at 3.25-3.5 post boil, so I need to get back to 4.25-4.5 pre boil. So, I will probably need to sparge. Long story short: Do the process & calculations seem sound? and would fellow BIABers recommend doing the dunk sparge or just pouring over the top of the grains style sparge? Thanks for your help, this will be my first AG/BIAB brew so any other tips are appreciated.

 

[tre9er]

I liked dunk-sparge and squeeze when I did BIAB. Pouring seems like there could be channels the water would run through and you'd miss some spots...but I've not done it.