Ihave a buzzer I hold to the shell with a pushbutton i work with my foot.
I have a 20 guage shell cut off to hold the right amount of Tru-square buffer, put a little handle on it.
Load shell, put dipper full into shell, hold against buzzer, step on switch. the buffer flows right into the load. The shot just sits there and spins around.
I never tried small shot sizes but this works for me.
HM