Do all of it in the keg.
I've got a DIPA with 1272 right now going. It's been a week I think since I brewed it, still appears to be working, but probably residual stuff clearing up.
I'm gonna give it another week, keg it, dry hop it with 3oz and carb it all at the same time. Let it sit for a week or whatever.
Bubba's Backyard Brewery