You should create an equipment profile for your specific equipment.
You're best off checking the boil off for your pot by boiling a measured amount of water for an hour, then checking the volume when the boil is done and cooled down. You're going to lose somewhere around 0.5 gallons to trub/cold break while chilling, so you can figure out, based on your boil off amount, the pre-boil volume you need to shoot for in order to end up with 5.5 gallons post boil.
Boil off is a constant, so in your boil off test it doesn't matter if you boil 6 gallons or 3 gallons, just put the amount of boil off in the appropriate field in the equipment profile.
Once you've got the pre-boil volume set in your equipment profile, your mash water and sparge water volumes will adjust to get you to that volume.
primary: CDA #2
primary: Evil Twin Red
primary: Mosaic Single Hop Pale
Bottled: Oddsides Citra Pale clone, India Cream Ale, CDA #1, Cascadian Dubbel
On deck: Surly Abrasive clone, Yooper's Pale Ale