Charging the capacitor more often means that the charging pulses will have a smaller peak value, which means that the ohmic losses will be reduced for a smaller difference between loaded and unloaded voltage output. For a given power output from your transmitter, the unloaded voltage on the plate is substantially smaller, reducing the risk for arcing. With a more sine wave like current on the mains, the lights in your and your neighbours house will not darken so much when you push the key - this is part of the reduced ohmic losses. I guess most amateurs consider it a bit extreme to use a 12 pulse DC supply for the power amplifier. I was lucky to find the transformers required, so I use now a 12 pulse supply with two three phase transformers, and I am pleased with the low voltage drop at key down.
Variable mains transformers Variable mains transformers are very useful.
If you can find one, use it to control anode and screen grid simultaneously. If you run your amplifier in variable class as described above, keeping a constant ratio between anode and screen grid corresponds to class C anode and screen grid modulation when the key is down. This means that the tuning is unchanged when the output power is changed. With a variable transformer controlling the voltage simultaneously for both anode and screen grid you can adjust the power by 20 dB or more. To maintain a reasonable idle current, of course the control grid negative voltage has to be reduced also.