You can use parts of MJ to rendez-vous with asteroids. Like matching planes. Once that is done you have to fiddle with the maneuver nodes to get an intercept and when you have it MJ can burn it (about a 10km max incounter). If you can get that part out of the way you can use MJ rendez-vous planner to get closer and match speed. Maneuver nodes are a bit better now, you can make minute ajustments when you scroll on those markers and you can add or detract extra orbits too. But MJ is mostly useless to fly an asteroid once you got it, especially the big ones. I did a class C and every time I did a new maneuver I had to redock to it so the center of mass was inline with the node. Hope this helps.