So it is inevitable to use PFC and a buck converter as you suggested ?
In that case, can I use a relatively small PFC output capacitor, which will cause larger voltage ripple ,
and let the buck converter deal with the varying input voltage (I will restrict the PFC cap not to fall below 320v, let's say.)
In any case, I should restrict the buck converter to a lower current/power than of the PFC, otherwise it will over-drain the PFC capacitor, to the point it will start charging with the bypass diode again.
Am I correct ?