Details later - empty entry for a reply.
Short story - Yend is now same as Xend filters-wise and lack of gain sliders -wise. Both ends have 13.7k resistors around the AD620 to give them gains of ~4.5.
Xend seems fine.
Yend seems not fine. Even the dark noise spectrum sees giganto peaks. See Diego's elog 10801 for details on this investigation.