Best way to lift the balls vertically

My team would like to build a vertical flywheel for the beginning of the season, but we don’t know how we would lift the hard plastic balls into our flywheel. Only thing we could think of are tank treads but they seem unreliable to me.

A quick and easy way to do this would be to use the vex tank tread inserts(link), and lift the balls up, dropping them into the flywheel. Attached is a terrible diagram of this concept.
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@Forrest Keller +100000000

team 6891 Jackpot had another way to do it in their nothing but net reveal