Hmm, i'd guess it doesn't matter, since lower tier roulettes will give law as well; so you could cap a DoH, and then get law with any of your DoW/M.
But DoH/L can't get law, and no gear to buy for them.
But i'm guessing that all the stuff you buy with law, are lv 60 stuff. So they might not want you to stock up on lv 60 gear, before you get to 60.