I brewed my first BarleyWine on 10/27, and it's still fermenting away (cooler temps to get something great from WLP099). Target is in the area of 15.3% (maybe higher) ABV. My plan is to leave it in primary until I know it's 100% finished fermenting. Then, transfer to one of my aging vessels, onto oak cubes, for X months before transferring to corny kegs to carbonate. I'm planning to bottle some once carbonated, to both age that way and give people (375ml Belgian bottles). While I could carbonate with priming solution, I don't want the extra sediment in the bottles.
I might transfer to a second aging vessel for this batch. It all depends on how it is when I check on it.