Do you already have the C4S upgrade for your Seduction?
Yes I do!
Too bad, the connections are going to be a puzzle. The idea is simple - use one 6922 as a dual shunt reg, keeping the other as the RIAA amp. But you would need four independent current sources, and the existing board has a single input and only two bias chains. And the newest PC boards do not quite fit the screw spacing of the current Seduction.
Let me think about the possibilities for a couple days, and ping me privately. As long as you do not need the cover shield box, I'm sure we can cobble something together.