Cap Feeder Line Speed Matching specification should start with the real closure.
The feeder should run fast enough to protect the capper but not so aggressively that it floods the chute or damages caps. Line speed matching looks at bottle rate, cap queue, feeder recovery time and the practical output of the selected sorting method.
For a better buying decision, the useful comparison is not only hopper size or headline speed. It is how the feeder behaves with your closure, how the capper receives the cap and how easy the line is to run after changeover.
The safest specification route is to start with real closures, target output, line photos and the exact point where the cap must be presented. That avoids choosing a feeder on a generic speed figure that does not match the cap or capper.