Different tools for different shapes. The roller wins on straight-walled cylinders because you just drop the item on and go — no chuck, no centring. The rotary wins on anything tapered, stepped, or where you need a known rotation reference (rings, stemware, bottles with a lip).
For 300 straight tumblers a month I'd use the roller and build a hard stop jig so every item lands in the same place. That's where your two minutes goes — not the clamping, the finding-centre-again. With a stop block you're at maybe fifteen seconds per item.
I sell a cradle file for exactly this but you can cut one from 6mm ply in twenty minutes. Two uprights, a V rest, a stop at one end, done.