Kiss, wouldn't it be easier to regulate to a lesser voltage, say 235V Ac or there abouts ?
I think the best solution may be to try the control first & then get a handle on what or what not needs to be done from there.
Just a thought, maybe it's what you have already mentioned but what about if the table went from 0 to say 95 & then compensate in the PID loop somehow for variation of the Process output or swing in the output.
Or would the Derivative part dampen this effect?
I sort of see it as a remote helicopter or something similar, say we are flying it with a PID controller & our set point maybe say 50ft altitude, only on very calm days does the PID not have to adjust as much. In normal flying conditions you have up draft, down draft, side draft & god knows what else etc so the PID adjusts to these conditions very quickly.
It's seems the same scenario with this controller where the mains may dip up or down, I think it just needs good fast dampened control to handle it.
Maybe I have no idea either but lets see if we can control this first & see how we go.
If I have no idea, just say so, I would haha!
I am just making up a proper circuit board now so things are safe.
Yes I tried very small resistances in the simulation but the output was erratic????
Cheers