Or, if you use a separate, fixed, screen supply, feed the screen through a
10 henry choke.This allows the screen to "float up" to audio frequencies.
I've done this several times with plate modulated 813s, both singly and in
parallel pairs.

73,
Joe K3ICO
"David J Windisch" wrote in message
.. .
Iirc, among tips for doing subject operation "much more better" is to feed
the screen-grid from a dropping-resistor connected to the modulated-DC
side of the modulation xfmr.
73, Dave, N3HE