[bonjour]

I would add A hAlf gallon too be sure and then adjust that to your results

[hampshirebrewer]

When I fly sparge I run it dry EXCEPT the cloudy, chunky final runnings don't make it into the brew kettle.

I calculate out the estimated final volume of runnings and make sure I leave at least a quart or two in my lauter tun.

So while I'm watching the kettle on the burner for the ever present threat of boilover, the remainders are draining to lighten the load to the compost pile.

My 6 gal bucket with false bottom system retains about .15 gallons per lb of grain. Less if I'm using a lot of flaked grains.