The reason the kit is 6 gallons into the fermentor is that there are so many dry hops and possibly as much trub which will result in significant (i.e. more than average) losses of beer when racking.
It will depend on how many times you rack it, how careful you are, etc…
As usual, I just ferment and dry hop right in the stainless boil kettle. I no longer use buckets or carboys.
If you decide to go that route, you can rack or strain into a bucket, clean and sanitize your BK and lid and then pour the wort back in. I use an 8 gallon BK (no problems with krausen) and fermented at 59F for the first week and 68F for the second week, then held at 68F for the following two weeks for dry hopping (all in the BK). F.G. of 1.011. Cold crashed and kegged. Gelatin in the keg. Couple days over 4 weeks total. Racking from the BK is a little tedious due to all the hops but really not that bad with a fine strainer paint bag (or 2).
If you desire to use a carboy or a bucket, you’ll need a 6.5 gallon with a blowoff assembly.