Are these flats or packers?
BTW, with the exception of one packer I cooked on my mini-WSM, every brisket I have BBQ'd in the last year has been on my 22.5" OTG (and I dare say as a relative novice to BBQ, with some pretty damned good success).
If you want to give yourself the most cooking space, I suggest using the snake/ring of fire method on your kettle. You can also bank the coals to one side behind some fire bricks and cook the briskets on the opposite side (although you will have less room, IME). The snake/ring of fire method works pretty well if you want to do LnS with one load of coals and no need for a water pan. I can get 10-12 hours at around 220 using this method which makes it great for overnight cooks.
The second method I find better for HnF (or MnM) cooks. Yes, you can do LnS on a kettle banking to one side, but temperature control is a little bit more difficult. That said, unless you have a large hunk of meat that you want to cook overnight, my limited experience is that HnF (or MnM) is a better way to go since you can get equally good results, with less time.
There are people here with WAAAAAAAAAAAY more experience BBQ'ing than I have here, but, I am willing to bet that I have a fair amount of experience cooking briskets on a kettle when compared to many here simply because I don't yet have a large capacity dedicated smoker (which I will remedy next weekend when I build my first UDS) and I am brisket-obsessed (I seem to cook more briskets than anything else).
BTW, if you are cooking flats and not packers, my advice is of limited help because I don't have much experience with flats, and the limited experience I did have with flats on a kettle were somewhat hit or miss. The best result I ever got with a flat was when I cooked at about 250 after injecting with beef broth until it hit the stall, then I foiled until it was tender. The only downside to this was that it didn't have the best bark.
22" OTG; 22" Performer; mini-WSM; Brinkmann gasser; UDS (on the way); Maverick ET-732