I'm not sure where the guide is getting 285 per from, but I'd highly suggest diving into Old Newgate with Watchful or Dangerous around 147. Guaranteed 250 an action after the first two so long as you stick to Set an Ambush/Sow Carnage and you can swap back the right attribute without losing that and without much risk. It's available as soon as you reach The University. I'd say it's by far the best grind for them.