Just a quick follow-up that can perhaps help someone else...
I ended-up purchasing a Crydom DC100D40, primarily because I was able to get it quickly and with free shipping, as opposed to the Auber relay that would unfortunately take a while to arrive and was very expensive to ship to my location.
I am now able to run up to 1kHz PWM frequency on the bed heater, although all light flicker disappears just above 100 Hz which is where I keep it. As another HUGE bonus, I am thrilled to have eliminated a potential fire hazard of the stock SSR.
The printer shipped with a DELIXI CDG1-1DD/40A SSR that was installed on two spacer posts with no heat sink of any kind. This SSR was running so hot in use that it was impossible to touch. For kicks, I measured the voltage drop on the SSR when it was on and my jaw dropped even more than the voltage when the multimeter registered 1.65V! This is equivalent to approximately 0.1 Ohm internal resistance, resulting in 27W of power being dissipated by the SSR while driving a 400W load. Unbelievable!
The Crydom DC100D40 under identical conditions measures 0.084 V drop, which is equivalent to just over 0.005 Ohm and 1.4W of power being dissipated. I mounted the Crydom on a small heat sink, per data sheet requirements, which in retrospect was totally unnecessary. The SSR stays cool to touch even under extended full load operation. Beautiful!