Continuous servos have no Continuous servos have no positional feedback. Think of them as just motors, can spin clockwise or counterclockwise at various speeds but you have no way to tell what angle the shaft is at. You want normal servos for arms and stuff.
Might be good to make Might be good to make estimates of the arm lengths, to calculate wheter a servo will be strong enough to move a weight at the end. A 43 oz-in (3 kg-cm) servo will move 43 oz (1.22 kg) on a 1 inch (2.54 cm) arm, or it will move 3.5 oz (0.1 kg) on a 12.3 inch (31.2 cm) arm.