Grifters deal in trust. They gain it, and then use it against the people who’ve entrusted it to them. They’re at their best in social situations and are good at acting, lying, and manipulating people. Pretending to be a businesswoman from Germany, convincing a Mark to buy a fake Rolex, or distracting a guard so the Hitter can knock him out would all be rolls made on Grifter.
Hackers deal in information. They get it for the Crew, deny it to the Mark, use it to help the Crew, or manipulate it to take the Mark down. They usually do this by cracking computer networks and security systems, but Hackers are also often good with physical tools and obtaining items the Crew needs. Hacking a network firewall, eavesdropping on the Mark’s cell phone, and “airbrushing” a photo ID would all be rolls made on Hacker. (Note: This campaign is set in 1969 and as such, current, modern technology does not exist. A lack of cell phones and microwaves won’t daunt an intrepid hacker, however, who knows how to make do with “stone knives and bear claws.”)
Hitters deal in force. They engage in direct combat to put force on bad guys, getting them out of the way. Engaging in combat, sizing up a tactical situation, and intimidating a guard would all be rolls made on Hitter.
Masterminds deal in plans. They formulate the plan at the start of the Job and coordinate the team’s efforts to stay on track. They deal with the unexpected events that threaten to blow every plan. Figuring out where the Mark might have hidden the money, noticing that three unexpected guards are coming in the front door, and guessing what sort of bribe would best win the Mark’s confidence would all be rolls made on Mastermind.
Thieves deal in access. They get themselves and the Crew access by breaking through security systems, and they use access to steal items or information. Sneaking past a guard, cartwheeling through a room of laser sensors, and picking the Mark’s pocket would all be rolls made on Thief.
Each Crew Member is an expert in one role, pretty good in another, average in a third, and not so good in the other two. For those two roles, it’s more fun if you pick the ones that you’d find interesting to complicate things with. Only the primary role needs to be determined beforehand, to ensure a balanced Crew.