I don't think it needs to be quite that complicated... Just have some kind of interface where the user can select which jobs they wish to have in the Roulette, with a minimum requirement of at least one job from each role. If the user mistakenly selects a job that they don't have the proper gear for - well, that's their bad. They'll time out of the Duty Commencement, earn a strike for the day, and know better for next time.