Using plaction wheels on a roller claw

Our team is working on our robot again, and we're thinking about changing our manipulator to a roller claw. We want a design with wheels the have a major grip advantage over other wheels, and though about using small plaction wheels on our roller claw. What we would like to know is, do you think this is effective? Does anybody have any suggestions on wheels? We want to be able to use our manipulator to both suck in tubes from the floor, and spit them out a few feet. We want to spit them out in a possible close-range feeding strategy.

Thanks!