Cap Feeder Speed Calculation specification should start with the real closure.
A cap feeder should not be selected on a headline speed alone. The calculated rate must include the capping machine demand, changeover losses, refill time, cap quality variation and the amount of buffer available in the chute.
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.